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Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-20T03:41:04Z

RubyGhani: /* Vancouver’s proneness to seismic activity */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Eneanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Eneanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for a natural disaster is a crucial element in minimizing the impact of seismic events in BC, Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, which urge to create emergency strategies, assemble emergency supply kits, and fasten household items. The research conducted did find that many individuals acknowledge the danger of a major earthquake, their level of preparedness is often low due to insufficient urgency and conflicting efforts. Raising public awareness and promoting proactive readiness can help aim to minimize future injuries, property loss, or disturbance caused after the earthquake. Being successful in preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react to disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==
BC’s position in the seismically active Cascadia area is extremely likely to be effected to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress. Which highly risk for a significant seismic occurrence referred to as “The Big One”. The studies that have been conducted highlighted that this type of earthquake may lead to intense destruction, liquefaction, landslides, and tsunamis across the Lower Mainland. The studies further examine the geological processes that influence earthquake risk in British Columbia; community readiness is crucial. Vancouver's geological features and earthquake hazards enable communities to be prepared for future disasters that could cause significant damage when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Eneanwan, E. J., Scherwath, M., Moran, K., Dosso, S. E., & Rohr, K. M.|date=(2023).|title=Fault slip tendency analysis for a deep-sea basalt CO2 injection in the Cascadia basin.|url=doi:https://doi.org/10.3390/geohazards4020008|journal=GeoHazards|volume=, 4(2), 121.}}</ref><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]
<references /><ref>{{Cite journal|last=Lynch, E. M.|date=(2023).|title=Strain accommodation on forearc faults: A case study on the Beaufort Range Fault, an active crustal fault in the northern Cascadia forearc, Vancouver Island, BC, Canada|url=https://www.proquest.com/dissertations-theses/strain-accommodation-on-forearc-faults-case-study/docview/2908234649/se-2|journal=a (Order No. 30688619). Available from ProQuest Dissertations & Theses Global. (2908234649). Retrieved from}}</ref>

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-20T03:40:43Z

RubyGhani: /* Geological impacts of “The Big One.” */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Eneanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for a natural disaster is a crucial element in minimizing the impact of seismic events in BC, Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, which urge to create emergency strategies, assemble emergency supply kits, and fasten household items. The research conducted did find that many individuals acknowledge the danger of a major earthquake, their level of preparedness is often low due to insufficient urgency and conflicting efforts. Raising public awareness and promoting proactive readiness can help aim to minimize future injuries, property loss, or disturbance caused after the earthquake. Being successful in preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react to disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==
BC’s position in the seismically active Cascadia area is extremely likely to be effected to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress. Which highly risk for a significant seismic occurrence referred to as “The Big One”. The studies that have been conducted highlighted that this type of earthquake may lead to intense destruction, liquefaction, landslides, and tsunamis across the Lower Mainland. The studies further examine the geological processes that influence earthquake risk in British Columbia; community readiness is crucial. Vancouver's geological features and earthquake hazards enable communities to be prepared for future disasters that could cause significant damage when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Eneanwan, E. J., Scherwath, M., Moran, K., Dosso, S. E., & Rohr, K. M.|date=(2023).|title=Fault slip tendency analysis for a deep-sea basalt CO2 injection in the Cascadia basin.|url=doi:https://doi.org/10.3390/geohazards4020008|journal=GeoHazards|volume=, 4(2), 121.}}</ref><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]
<references /><ref>{{Cite journal|last=Lynch, E. M.|date=(2023).|title=Strain accommodation on forearc faults: A case study on the Beaufort Range Fault, an active crustal fault in the northern Cascadia forearc, Vancouver Island, BC, Canada|url=https://www.proquest.com/dissertations-theses/strain-accommodation-on-forearc-faults-case-study/docview/2908234649/se-2|journal=a (Order No. 30688619). Available from ProQuest Dissertations & Theses Global. (2908234649). Retrieved from}}</ref>

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-20T03:39:40Z

RubyGhani: /* References */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for a natural disaster is a crucial element in minimizing the impact of seismic events in BC, Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, which urge to create emergency strategies, assemble emergency supply kits, and fasten household items. The research conducted did find that many individuals acknowledge the danger of a major earthquake, their level of preparedness is often low due to insufficient urgency and conflicting efforts. Raising public awareness and promoting proactive readiness can help aim to minimize future injuries, property loss, or disturbance caused after the earthquake. Being successful in preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react to disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==
BC’s position in the seismically active Cascadia area is extremely likely to be effected to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress. Which highly risk for a significant seismic occurrence referred to as “The Big One”. The studies that have been conducted highlighted that this type of earthquake may lead to intense destruction, liquefaction, landslides, and tsunamis across the Lower Mainland. The studies further examine the geological processes that influence earthquake risk in British Columbia; community readiness is crucial. Vancouver's geological features and earthquake hazards enable communities to be prepared for future disasters that could cause significant damage when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Eneanwan, E. J., Scherwath, M., Moran, K., Dosso, S. E., & Rohr, K. M.|date=(2023).|title=Fault slip tendency analysis for a deep-sea basalt CO2 injection in the Cascadia basin.|url=doi:https://doi.org/10.3390/geohazards4020008|journal=GeoHazards|volume=, 4(2), 121.}}</ref><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]
<references /><ref>{{Cite journal|last=Lynch, E. M.|date=(2023).|title=Strain accommodation on forearc faults: A case study on the Beaufort Range Fault, an active crustal fault in the northern Cascadia forearc, Vancouver Island, BC, Canada|url=https://www.proquest.com/dissertations-theses/strain-accommodation-on-forearc-faults-case-study/docview/2908234649/se-2|journal=a (Order No. 30688619). Available from ProQuest Dissertations & Theses Global. (2908234649). Retrieved from}}</ref>

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-20T03:36:25Z

RubyGhani:

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for a natural disaster is a crucial element in minimizing the impact of seismic events in BC, Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, which urge to create emergency strategies, assemble emergency supply kits, and fasten household items. The research conducted did find that many individuals acknowledge the danger of a major earthquake, their level of preparedness is often low due to insufficient urgency and conflicting efforts. Raising public awareness and promoting proactive readiness can help aim to minimize future injuries, property loss, or disturbance caused after the earthquake. Being successful in preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react to disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==
BC’s position in the seismically active Cascadia area is extremely likely to be effected to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress. Which highly risk for a significant seismic occurrence referred to as “The Big One”. The studies that have been conducted highlighted that this type of earthquake may lead to intense destruction, liquefaction, landslides, and tsunamis across the Lower Mainland. The studies further examine the geological processes that influence earthquake risk in British Columbia; community readiness is crucial. Vancouver's geological features and earthquake hazards enable communities to be prepared for future disasters that could cause significant damage when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]
<references /><ref>{{Cite journal|last=Lynch, E. M.|date=(2023).|title=Strain accommodation on forearc faults: A case study on the Beaufort Range Fault, an active crustal fault in the northern Cascadia forearc, Vancouver Island, BC, Canada|url=https://www.proquest.com/dissertations-theses/strain-accommodation-on-forearc-faults-case-study/docview/2908234649/se-2|journal=a (Order No. 30688619). Available from ProQuest Dissertations & Theses Global. (2908234649). Retrieved from}}</ref>

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-20T03:35:02Z

RubyGhani:

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for a natural disaster is a crucial element in minimizing the impact of seismic events in BC, Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, which urge to create emergency strategies, assemble emergency supply kits, and fasten household items. The research conducted did find that many individuals acknowledge the danger of a major earthquake, their level of preparedness is often low due to insufficient urgency and conflicting efforts. Raising public awareness and promoting proactive readiness can help aim to minimize future injuries, property loss, or disturbance caused after the earthquake. Being successful in preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react to disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==
BC’s position in the seismically active Cascadia area is extremely likely to be effected to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress. Which highly risk for a significant seismic occurrence referred to as “The Big One”. The studies that have been conducted highlighted that this type of earthquake may lead to intense destruction, liquefaction, landslides, and tsunamis across the Lower Mainland. The studies further examine the geological processes that influence earthquake risk in British Columbia; community readiness is crucial. Vancouver's geological features and earthquake hazards enable communities to be prepared for future disasters that could cause significant damage when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-19T12:53:33Z

RubyGhani:

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure <ref name=":5">{{Cite journal|last=Claque, J. J., Naesgaard, E., & Nelson, A. R.|date=1997.|title=Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada.|url=https://doi.org/10.1139/t96-081|journal=Canadian Geotechnical Journal, 34|volume=1|pages=53-62}}</ref>. Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past <ref name=":5" />. Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas <ref name=":6">{{Cite journal|last=Simms, A. R., DeWitt, R., Zurbuchen, J., & Vaughan, P.|date=2017.|title=Coastal erosion and recovery from a Cascadia subduction zone earthquake and tsunami.|journal=Marine Geology|volume=392|pages=30-40}}</ref>. Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time <ref name=":6" />.

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels <ref name=":7">{{Cite journal|last=Dura, T., Chilton, W., Small, D., Garner, A. J., Hawkes, A., Melgar, D., Engelhart, S. E., Staisch, L. M., Witter, R. C., Nelson, A. R., Kelsey, H. M., Allan, J. C., Bruce, D., DePaolis, J., Priddy, M., Briggs, R. W., Weiss, R., La Selle, S. P., Willis, M., & Horton, B. P.|date=2025.|title=Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise.|journal=Proceedings of the National Academy of Sciences, 122|volume=18|pages=e2424659122.}}</ref>. This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding <ref name=":7" /><ref name=":6" />. In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century <ref name=":7" />.

When considered together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates <ref name=":8">{{Cite journal|last=Bornhold, B. D., & Yorath, C. J.|date=1984.|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=Marine Geology, 57|volume=(1-4)|pages=89-112.}}</ref>. Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction <ref name=":8" />. This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation <ref name=":8" />. Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone <ref>{{Cite journal|last=Goda, K., & Sharipov, A.|date=2021.|title=Fault-source-based probabilistic seismic hazard and risk analysis for Victoria, British Columbia, Canada: A case of the leech river valley fault and Devil’s mountain fault system.|url=https://doi.org/10.3390/su13031440|journal=Sustainability, 13|volume=(3)|pages=1440}}</ref>. Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California <ref name=":9">{{Cite journal|last=Kakoty, P., Molina Hutt, C., Ghofrani, H., & Molnar, S.|date=2023.|title=Spectral acceleration basin amplification factors for interface Cascadia subduction zone earthquakes in Canada’s 2020 national seismic hazard model.|url=https://doi.org/10.1177/87552930231168659|journal=Earthquake Spectra, 39|volume=(2)|pages=1166-1188.}}</ref>. The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 <ref name=":9" />. Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure <ref name=":9" />. The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes <ref>{{Cite journal|last=Hyndman, R. D., Wang, K., Yuan, T., & Spence, G. D.|date=1993.|title=Tectonic sediment thickening, fluid expulsion, and the thermal regime of subduction zone accretionary prisms: The Cascadia margin off Vancouver Island. |url=https://doi.org/10.1029/93JB02391|journal=Journal of Geophysical Research: Solid Earth, 98|volume=B12|pages=21865-21876}}</ref>'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes <ref name=":9" />. Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits <ref name=":9" />. These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid <ref name=":3" />'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility <ref name=":4" />'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake <ref name=":4" />.

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. <ref name=":10">{{Cite journal|last=Costa, R., Haukaas, T., & Chang, S. E.|date=2021.|title=Agent-based model for post-earthquake housing recovery.|url=https://doi.org/10.1177/8755293020944175|journal=Earthquake Spectra, 37|volume=1|pages=46-71}}</ref>, recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 <ref name=":10" />. Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when <ref name=":10" />. Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition <ref name=":10" />.

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos <ref>{{Cite journal|last=Mattos, M. B.|date=2022.|title=The working class from Marx to our times.|url=https://link.springer.com/book/10.1007/978-3-030-97355-1|journal=Springer Nature.}}</ref> explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. <ref name=":11">{{Cite journal|last=Breau, S., Shin, M., & Burkhart, N.|date=2017.|title=Pulling apart: New perspectives on the spatial dimensions of neighbourhood income disparities in Canadian cities.|url=https://doi.org/10.1007/s10109-017-0255-0|journal=Journal of Geographical Systems, 20|volume=1|pages=1-25}}</ref> explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. <ref name=":11" /> find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated <ref name=":11" />.

For the case of Vancouver, Costa et al. <ref name=":10" /> explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. <ref name=":10" /> explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery; however, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure <ref name=":12">{{Cite journal|last=Costa, R., & Haukaas, T. (2021).|title=The effect of resource constraints on housing recovery simulations.|url=https://doi.org/10.1016/j.ijdrr.2021.102071|journal=International Journal of Disaster Risk Reduction|volume=55|pages=102071}}</ref>. If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) <ref name=":12" />. Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. <ref name=":12" />.

Badal & Tesfamariam <ref name=":13">{{Cite journal|last=Badal, P. S., & Tesfamariam, S. (2023)|title=Seismic resilience of typical code-conforming RC moment-frame buildings in Canada.|url=https://doi.org/10.1177/87552930221145455|journal=Earthquake Spectra, 39|volume=2|pages=748-771.}}</ref> explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. <ref name=":12" /> explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities <ref name=":12" />.

As we know, however, sociological considerations tell us that neighbourhoods based on class and income also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community <ref name=":11" />. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. <ref name=":14">{{Cite journal|last=Shiba, K., Hikichi, H., Okuzono, S. S., VanderWeele, T. J., Arcaya, M., Daoud, A., Cowden, R. G., Yazawa, A., Zhu, D. T., Aida, J., Kondo, K., & Kawachi, I. (2022).|title=Long-term associations between disaster-related home loss and health and well-being of older survivors: Nine years after the 2011 Great East Japan earthquake and tsunami.|url=https://doi.org/10.1289/ehp10903|journal=Environmental Health Perspectives, 130|volume=(7)|pages=1-10.}}</ref> describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing <ref name=":14" />. This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals <ref name=":14" />. These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. =<ref name=":14" />, is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. <ref>{{Cite journal|last=Ceferino, L., Mitrani, J., Kiremidjian, A., Deierlein, G., & Bambarén, C. (2019).|title=Effective plans for hospital system response to earthquake emergencies.|url=https://doi.org/1031224/osf.io/nyqug|journal=Nature Communications, 11|volume=(1)|pages=1-12.}}</ref> explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 <ref name=":15">{{Cite web|date=n.d.|title=1700 Cascadia subduction zone earthquake.|url=https://pnsn.org/education/pnw-earthquakes/notable/1700-cascadia|url-status=live|access-date=June 17, 2026.|website=Pacific Northwest Seismic Network.}}</ref>. Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years <ref name=":15" />. Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line <ref name=":1" />. Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" <ref name=":13" />. Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors <ref name=":10" />. With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. <ref name=":12" /> and Badal & Tesfamariam <ref name=":13" /> corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-19T03:54:33Z

RubyGhani: /* References */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure (Clague, Naesgaard, & Nelson, 1997). Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past (Clague, Naesgaard, & Nelson, 1997). Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas (Simms et al., 2017). Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time (Simms et al., 2017).

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels (Dura et al., 2025). This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding (Dura et al., 2025; Simms et al., 2017). In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century (Dura et al., 2025).

Taken together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates.<ref>{{Cite journal|last=Bornhold & Yorath|date=1984|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=}}</ref> Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction (Bornhold & Yorath, 1984). This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation (Bornhold & Yorath, 1984). Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone (Goda & Sharipov, 2021). Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California (Kakoty et al, 2023). The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 (Kakoty et al, 2023). Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure (Kakoty et al, 2023). The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes (Hyndman & Wang, 1993)'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes (Kakoty et al, 2023). Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits (Kakoty et al, 2023). These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid (Teixeira, 2024)'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility (Hu, 2021)'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake (Hu, 2021).

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. (2021), recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 (Costa et al., p. 47). Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when (ibid.). Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition (Costa and Haukaas 2021).

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos (2022) explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. (2017) explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. (2017) find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated (ibid., pp. 5-6).

For the case of Vancouver, Costa et al. (2021) explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. (2021) explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery. However, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure (Costa et al. 2021). If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) (ibid., p. 62). Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. (2021).

Badal and Tesfamariam (2023) explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. (2021) explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities (ibid., p. 49).

As we know, however, sociological considerations tell us that neighbourhoods based on class and income (Breau et al. 2017) also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. (2022) describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing (ibid., p. 1). This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals (ibid.). These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. (2022), is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. (2019) explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 (Pacific Northwest Seismic Network, n.d.). Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years (Pacific Northwest Seismic Network, n.d.). Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line (Frank, 2016). Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for earthquakes is a crucial element in minimizing the effects of significant seismic events in Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, inhabitants are urged to create emergency strategies, assemble emergency supply kits, and fasten household items that might result in injury during significant ground shaking. The research that was conducted discovered that although numerous individuals acknowledge the dangers of a significant earthquake, their preparedness levels frequently stay low because of insufficient urgency and faith in their preparation efforts. Raising public awareness and promoting proactive readiness can aid in minimizing injuries, property loss, and disturbances after a major earthquake. Successful preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react during disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" (Badal and Tesfamariam 2023). Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors (Costa et al. 2021). With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. (2021) and Badal and Tesfamariam (2023) corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==

Vancouver’s BC’s position in the seismically active Cascadia area renders it extremely susceptible to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress, which poses a risk for a significant seismic occurrence referred to as "The Big One." Studies that have been highlighted that this type of earthquake may lead to intense ground shaking, liquefaction, landslides, and tsunamis, which would cause considerable destruction to infrastructure across the Lower Mainland. As researchers have conducted numerous studies on the geological processes that influence earthquake risks in British Columbia, community readiness is also crucial. Grasping Vancouver's geological features and earthquake hazards enables communities to enhance their preparedness for future calamities and lessen the effects of a significant seismic incident when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references responsive="0" /><ref>{{Cite journal|last=Asgarizadeh Lamjiry, Z., & Gifford, R.|date=2022|title=Earthquake threat! Understanding the intention to prepare for the big one. Risk Analysis:|url=https://doi.org/10.1111/risa.13775|journal=An Official Publication of the Society for Risk Analysis,|pages=42(3), 487–505.}}</ref>{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-18T06:31:18Z

RubyGhani: /* Conclusion */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure (Clague, Naesgaard, & Nelson, 1997). Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past (Clague, Naesgaard, & Nelson, 1997). Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas (Simms et al., 2017). Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time (Simms et al., 2017).

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels (Dura et al., 2025). This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding (Dura et al., 2025; Simms et al., 2017). In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century (Dura et al., 2025).

Taken together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates.<ref>{{Cite journal|last=Bornhold & Yorath|date=1984|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=}}</ref> Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction (Bornhold & Yorath, 1984). This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation (Bornhold & Yorath, 1984). Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone (Goda & Sharipov, 2021). Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California (Kakoty et al, 2023). The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 (Kakoty et al, 2023). Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure (Kakoty et al, 2023). The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes (Hyndman & Wang, 1993)'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes (Kakoty et al, 2023). Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits (Kakoty et al, 2023). These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid (Teixeira, 2024)'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility (Hu, 2021)'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake (Hu, 2021).

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. (2021), recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 (Costa et al., p. 47). Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when (ibid.). Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition (Costa and Haukaas 2021).

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos (2022) explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. (2017) explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. (2017) find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated (ibid., pp. 5-6).

For the case of Vancouver, Costa et al. (2021) explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. (2021) explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery. However, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure (Costa et al. 2021). If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) (ibid., p. 62). Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. (2021).

Badal and Tesfamariam (2023) explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. (2021) explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities (ibid., p. 49).

As we know, however, sociological considerations tell us that neighbourhoods based on class and income (Breau et al. 2017) also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. (2022) describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing (ibid., p. 1). This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals (ibid.). These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. (2022), is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. (2019) explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 (Pacific Northwest Seismic Network, n.d.). Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years (Pacific Northwest Seismic Network, n.d.). Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line (Frank, 2016). Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for earthquakes is a crucial element in minimizing the effects of significant seismic events in Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, inhabitants are urged to create emergency strategies, assemble emergency supply kits, and fasten household items that might result in injury during significant ground shaking. The research that was conducted discovered that although numerous individuals acknowledge the dangers of a significant earthquake, their preparedness levels frequently stay low because of insufficient urgency and faith in their preparation efforts. Raising public awareness and promoting proactive readiness can aid in minimizing injuries, property loss, and disturbances after a major earthquake. Successful preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react during disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" (Badal and Tesfamariam 2023). Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors (Costa et al. 2021). With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. (2021) and Badal and Tesfamariam (2023) corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==

Vancouver’s BC’s position in the seismically active Cascadia area renders it extremely susceptible to earthquakes. The Cascadia Subduction Zone has active tectonic faults and continuous tectonic stress, which poses a risk for a significant seismic occurrence referred to as "The Big One." Studies that have been highlighted that this type of earthquake may lead to intense ground shaking, liquefaction, landslides, and tsunamis, which would cause considerable destruction to infrastructure across the Lower Mainland. As researchers have conducted numerous studies on the geological processes that influence earthquake risks in British Columbia, community readiness is also crucial. Grasping Vancouver's geological features and earthquake hazards enables communities to enhance their preparedness for future calamities and lessen the effects of a significant seismic incident when it happens.

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines (KM)
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-18T06:24:06Z

RubyGhani: /* Earthquake Preparedness */

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure (Clague, Naesgaard, & Nelson, 1997). Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past (Clague, Naesgaard, & Nelson, 1997). Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas (Simms et al., 2017). Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time (Simms et al., 2017).

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels (Dura et al., 2025). This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding (Dura et al., 2025; Simms et al., 2017). In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century (Dura et al., 2025).

Taken together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates.<ref>{{Cite journal|last=Bornhold & Yorath|date=1984|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=}}</ref> Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction (Bornhold & Yorath, 1984). This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation (Bornhold & Yorath, 1984). Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone (Goda & Sharipov, 2021). Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California (Kakoty et al, 2023). The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 (Kakoty et al, 2023). Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure (Kakoty et al, 2023). The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes (Hyndman & Wang, 1993)'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes (Kakoty et al, 2023). Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits (Kakoty et al, 2023). These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid (Teixeira, 2024)'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility (Hu, 2021)'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake (Hu, 2021).

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. (2021), recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 (Costa et al., p. 47). Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when (ibid.). Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition (Costa and Haukaas 2021).

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos (2022) explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. (2017) explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. (2017) find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated (ibid., pp. 5-6).

For the case of Vancouver, Costa et al. (2021) explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. (2021) explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery. However, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure (Costa et al. 2021). If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) (ibid., p. 62). Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. (2021).

Badal and Tesfamariam (2023) explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. (2021) explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities (ibid., p. 49).

As we know, however, sociological considerations tell us that neighbourhoods based on class and income (Breau et al. 2017) also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. (2022) describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing (ibid., p. 1). This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals (ibid.). These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. (2022), is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. (2019) explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 (Pacific Northwest Seismic Network, n.d.). Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years (Pacific Northwest Seismic Network, n.d.). Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line (Frank, 2016). Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===
Being prepared for earthquakes is a crucial element in minimizing the effects of significant seismic events in Vancouver. Due to the area's susceptibility to earthquakes from the Cascadia Subduction Zone and local crustal faults, inhabitants are urged to create emergency strategies, assemble emergency supply kits, and fasten household items that might result in injury during significant ground shaking. The research that was conducted discovered that although numerous individuals acknowledge the dangers of a significant earthquake, their preparedness levels frequently stay low because of insufficient urgency and faith in their preparation efforts. Raising public awareness and promoting proactive readiness can aid in minimizing injuries, property loss, and disturbances after a major earthquake. Successful preparedness enhances community resilience and boosts the capacity of individuals and emergency services to react during disasters (Asgarizaeh Lamjiry & Gifford, 2022).

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" (Badal and Tesfamariam 2023). Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors (Costa et al. 2021). With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. (2021) and Badal and Tesfamariam (2023) corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/“The Big One”: An Analysis on Potential Socioeconomic and Public Health Impacts on Greater Vancouver

2026-06-18T06:17:39Z

RubyGhani: adding

==Introduction==

Are we ready for “the big one”?

Residents of Vancouver, British Columbia, are familiar with this term. When it comes to the topic of earthquakes, they know that "the big one" that is suspected to affect the city. British Columbia's West Coast finds itself at the edge of the North American Continental Tectonic Plate and in great likelihood of interacting with the Juan de Fuca Oceanic Tectonic Plate. Previous seismic activities have given British Columbia its islands and its remarkable mountains, but the residents of Vancouver are aware that the talks of this high-impact earthquake are true and can seriously affect the city and all they hold dear to it. The uncertainty of when "the big one" will hit and what will follow is what gives these British Columbians chills.

Our project aims to explore how earthquakes and its underlying geological processes (i.e. tectonic plates and fault systems) can impact communities in and around Vancouver in unequal ways. We investigate the geological factors that render certain communities more vulnerable to earthquake damage (ex. soil composition, proximity to fault lines, and proximity to bodies of water). By looking at wealth disparities, infrastructure quality, and access to healthcare services, our project analyzes how socioeconomic status can influence earthquake preparedness, recovery, and long-term outcomes after seismic events. Ultimately, the goal of this project would be to connect topics related to Earth Science with social impacts to better understand how natural hazards can amplify and deepen existing inequalities.

Though we understand that there is a level of speculation in which we would engage, we think that using a sociological lens to investigate this topic will strengthen understandings of how to protect the Earth and protect humans – both of which are pillars of the study of Geology.

Please note that this begins as a group project for the ''Geology and Our Majors'' assignment in UBC's EOSC 311 course. The initial authors in EOSC 311 come from backgrounds in Arts and intend to understand the deep interconnectedness of their Sociology discipline to Geology and Earth Science.

==Earthquakes==

=== Plate Tectonics ===
The theory of plate tectonics suggests that Earth's outer shell (the lithosphere) is divided into rigid plates that move relative to each other, driven by Earth's internal heat <ref name=":0">{{Cite web|date=n.d.|title=Plate Tectonics|url=https://ugc.berkeley.edu/background-content/plate-tectonics/|url-status=live|access-date=June 17, 2026|website=Understanding Global Change}}</ref>. Over the course of billions of years, these are forces that have been responsible for processes such as seafloor spreading, mountain building, volcanism, and earthquakes. The Pacific Ocean basin provides a particularly important record of plate motion, preserving evidence of plate fragmentation, spreading centres, and changing plate boundaries over the past 100 million years <ref>{{Cite journal|last=Wright, N. M., Seton, M., Williams, S. E., & Müller, R. D.|date=2015|title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin.|journal=Earth-Science Reviews|volume=154|pages=138-173}}</ref>.

At convergent plate boundaries, one tectonic plate may be forced beneath another in a process known as subduction <ref name=":0" />. Along the Cascadia margin of western North America, the Juan de Fuca plate system is actively subducting beneath the North American plate <ref name=":1">{{Cite journal|last=Frank, W. B.|date=2016|title=Slow slip hidden in the noise: The intermittence of tectonic release|url=https://doi.org/10.1002/2016GL069537|journal=Geophysical Research Letters|volume=43(19)|pages=10, 125-10, 133}}</ref>. Research suggests that the northern end of the subduction zone is quite complex in practice, given that it involves plate fragmentation, transform faulting, and deformation associated with the Explorer microplate and the Nootka Fault Zone <ref>{{Cite journal|last=Savard, G., Bostock, M. G., Hutchinson, J., Kao, H., Christensen, N. I., & Peacock, S. M|date=2020|title=The Northern Terminus of Cascadia Subduction|journal=Journal of Geophysical Research: Solid Earth|volume=125}}</ref>.

Not all plate motion is released through large earthquakes. It has been found that some tectonic strain is accommodated by slow slip events, which is characterized by episodes of fault movement that occur over days to months without producing strong seismic shaking <ref name=":1" />. Studies coming from Cascadia and Guerrero, Mexico, demonstrate that these slow slip events are often associated with tectonic tremor and low-frequency earthquakes, indicating that plate boundaries can release accumulated stress through a spectrum of behaviours that range between steady sliding to major earthquakes <ref name=":1" />.

=== Soil Composition and Liquefaction ===
Soil composition plays a critical role in determining how the ground responds to shaking caused by an earthquake <ref name=":2">{{Cite journal|last=Cassidy, J.F., Mucciarelli, M.|date=2010.|title=The importance of ground-truthing for earthquake site response|journal=Conference of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering|volume=758}}</ref>. Different soil types transmit and amplify seismic waves in different ways, which means that local geology can significantly influence the severity of ground shaking. Soft, unconsolidated sediments such as sand, silt, and clay often amplify earthquake vibrations more than solid bedrock, increasing the potential for structural damage <ref name=":2" /><ref name=":3">{{Cite journal|last=Teixeira, F.|date=2024.|title=Mechanisms to explain soil liquefaction triggering, development, and persistence during an earthquake.|url=https://doi.org/10.1016/j.eqs.2024.07.003|journal=Earthquake Science,|volume=37(6)|pages=558-573}}</ref>. Research has found that factors such as soil density, grain size, groundwater conditions, and sediment thickness all contribute towards seismic behaviour and site response <ref name=":4">{{Cite journal|last=Hu, J., Tan, Y., & Zou, W.|first=2021.|title=Key factors influencing earthquake-induced liquefaction and their direct and mediation effects.|url=https://doi.org/10.1371/journal.pone.0246387|journal=PloS One|volume=16(2)|pages=e0246387}}</ref><ref name=":2" />. In particular, areas underlain by thick sedimentary deposits can experience stronger and longer-lasting shaking than nearby bedrock sites because seismic energy can become amplified within softer sediments, allowing for more opportunity for the land to be disrupted <ref name=":3" />.

One of the most significant earthquake hazards associated with certain soil compositions is liquefaction. Liquefaction occurs when loose, water-saturated soils, especially fine sands and silty sands, temporarily lose their strength during intense ground shaking and begin to behave like a liquid <ref name=":4" />. As vibrations from an earthquake increase pore-water pressure within the sediment, the soil particles lose contact with one another, causing the ground to weaken and deform <ref name=":4" />'''.''' This process can produce features, such as sand blows, sand dikes, ground settlement, and lateral spreading, which can all severely damage infrastructure (Clague, Naesgaard, & Nelson, 1997). Studies of the Fraser River Delta near Vancouver have documented ancient features of liquefaction, which include large sand blows and sand dikes that are formed by strong prehistoric earthquakes, demonstrating that earthquake-induced liquefaction has occurred in western Canada in the past (Clague, Naesgaard, & Nelson, 1997). Groundwater depth, soil type, grain-size distribution, sediment age, and earthquake magnitude all influence the likelihood of liquefaction occurring during a seismic event <ref name=":4" /><ref name=":3" />.

=== Impacts of water on the coastline ===
Earthquakes present immediate and long-lasting impacts on coastlines by generating tsunamis, which leads to coastal erosion and altering shoreline elevations. Tsunami waves generated by large subduction-zone earthquakes possess enough energy to erode beaches, dunes, and coastal sediments over large areas (Simms et al., 2017). Research on the Cascadia Subduction Zone found that a prehistoric earthquake and tsunami eroded more than 225,000 ± 28,000 m³ of sand along a 1.7 km section of the northern California coast, with erosion extending over 110 m inland from the shoreline. Following the event, coastal recovery occurred through sediment redistribution and renewed beach progradation, although the shoreline morphology had remained altered for an extended amount of time (Simms et al., 2017).

In addition to erosion, earthquakes can permanently increase coastal flooding through land subsidence. During major subduction-zone earthquakes, sections of the coastline can suddenly sink by 0.5 to 2 m by the minute, rapidly raising local sea levels (Dura et al., 2025). This subsidence expands floodplains, increases the frequency of tidal inundation, and leaves coastal communities, infrastructure, and ecosystems more vulnerable to future flooding (Dura et al., 2025; Simms et al., 2017). In the Pacific Northwest, researchers estimate that earthquake-driven subsidence could more than double the number of residents, structures, and roads exposed to flooding, while future climate-driven sea-level rise could further amplify these impacts by the end of the century (Dura et al., 2025).

Taken together, the tsunami-induced erosion and long-term subsidence demonstrates that earthquakes possess the ability to reshape coastlines through rapid physical changes and persistent increases in coastal flood hazards.[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Greater Vancouver's Geology==

=== Vancouver’s geology and proximity to fault lines ===
Vancouver is situated in what is considered to be a geologically active region of southwestern British Columbia, where its landscape has been shaped by tectonic processes associated with the interaction of the North American, Juan de Fuca, and Explorer plates.<ref>{{Cite journal|last=Bornhold & Yorath|date=1984|title=Surficial geology of the continental shelf, northwestern Vancouver Island|journal=}}</ref> Offshore of Vancouver Island, the continental margin lies along a convergent plate boundary where the oceanic Juan de Fuca and Explorer plates are being forced underneath the North American Plate through subduction (Bornhold & Yorath, 1984). This geological context has produced produced extensive faulting, folding, and deformation throughout the region and remains the primary source of seismic hazard in western Canada. Geological studies of the Vancouver Island margin describe the area as an active Convergent boundary characterized by major thrust faults and ongoing crustal deformation (Bornhold & Yorath, 1984). Seismic activity in southwestern British Columbia originates from three primary sources: shallow crustal earthquakes, deep-in slab earthquakes within the subducting Juan de Fuca Plate, and mega-thrust earthquakes generated along the Cascadia Subduction Zone (Goda & Sharipov, 2021). Furthermore, the Juan de Fuca Plate continues to converge beneath the North American Plate at a rate of approximately 40 mm per year, demonstrating that the tectonic processes at play are responsible for regional deformation and earthquake generation that remain active today.

One of the most significant earthquake sources affecting Vancouver is the Cascadia Subduction Zone, which is a roughly 1,000 km long mega-thrust fault that extends from Vancouver Island to northern California (Kakoty et al, 2023). The fault is capable of generating very large interface earthquakes, including events approaching magnitude 9 (Kakoty et al, 2023). Canada's national seismic hazard model identifies Cascadia earthquakes as major contributors to seismic risk in southwestern British Columbia, particularly at longer vibration periods relevant to tall buildings and critical infrastructure (Kakoty et al, 2023). The Cascadia Subduction Zone has estimated recurrence interval of approximately 500 years for its largest earthquakes, making it one of the most important seismic threats to the Metro Vancouver region. The Cascadia margin is also characterized by an extensive accretionary prism, where sediments scraped from the subducting oceanic plate are compressed, thickened, and deformed along the continental margin. Studies of the prism west of Vancouver Island indicate ongoing sediment accretion, fluid expulsion, and deformation associated with active subduction processes, providing further evidence that the Cascadia system remains tectonically active and capable of generating major earthquakes (Hyndman & Wang, 1993)'''.'''

In addition to its proximity to major fault systems, Vancouver's earthquake hazard is amplified by local geological conditions. Much of Metro Vancouver overlies the Georgia sedimentary basin, which is a deep accumulation of sediments that can significantly increase ground shaking during large earthquakes (Kakoty et al, 2023). Research using stimulations of magnitude 9 Cascadia events found that basin amplification effects can substantially increase long-period ground motions compared to sites outside the basin, with the strongest amplifications occurring in the deepest portions of the sedimentary deposits (Kakoty et al, 2023). These basin effects can intensify shaking experienced by mid and high-rise structures, thereby increasing the potential for damage during a major subduction zone earthquake.

Furthermore, the region's sedimentary geology contributes to a heightened risk of earthquake-induced liquefaction, particularly in low-lying areas supported by young, water-saturated sands and silts. Liquefaction occurs when strong seismic shaking causes saturated soils to temporarily lose strength and behave like a fluid (Teixeira, 2024)'''.''' Studies have identified that earthquake magnitude, peak ground acceleration, groundwater depth, soil composition, grain size, and shear-wave velocity acts as key factors that control liquefaction susceptibility (Hu, 2021)'''.''' As a result, areas that are built on unconsolidated sediments, including portions of the Fraser River delta and surrounding coastal lowlands, may experience ground settlement, lateral spreading, and infrastructure damage during a major Cascadia earthquake (Hu, 2021).

=== Vancouver’s proneness to seismic activity ===
The research indicated that the southwest of British Columbia experiences frequent seismic activity due to the interaction of multiple fault systems within the Cascadia region. The active faults throughout the forearc region continue to accumulate strain, which increases the potential for future earthquakes (Lynch, 2023). Most earthquakes are small and cause little damage. Geologists do estimate that the Cascadia Subduction Zone is capable of producing a magnitude 8 to about 9 megathrust earthquake, which is referred to as “The Big One”. Studies examining public awareness or preparedness suggest that many residents recognize the earthquake threat but remain inadequately prepared for a major event (Asgarizaeh Lamjiry & Gifford, 2022).

Vancouver has three main types of earthquakes: shallow crustal earthquakes, deep in slab earthquake witghin the Juan de Fuca Plate, and megathrust earthquakes that is at the Cascadia Subduction Zone. These three different seismic sources increase the region's earthquake risk. Forearc faults play a significant role in accommodating strain across the Cascadia region, which means that earthquake hazards are distributed across the faults raryher beginning confined to a single fault (Lynch, 2023).

Research that was conducted throughout the Cascadia Basin demonstrated that fault in the offshore basin. It remains sensitive to stress change and may be susceptible to movement that under geological conditions. The study did focus on potential carbon dioxide storage in an active stress regime that characterizes the Cascadia margin (Ilheanwan et al., 2023).

=== Geological impacts of “The Big One.” ===
The major earthquake would likely cause widespread geological impacts across BC and the Vancouver region. The ground shaking could trigger numerous soft-built sediments, specifically along the river deltas and reclaimed land. Landslides may occur on steep slopes throughout the Lower Mainland and surrounding regions. Coastal areas could experience subsidence and tsunami effects; bridges, roads, ports, and utilities could face extreme damage. The research conducted on the fault behavior in the Cacadia Basin examines the active tectonic stresses throughout the region. The potential for large scale fault movement during seismic events (Ilheanwan et al., 2023). The combination of intense ground shaking and secondary hazards that cause risks for Vancouver is one of Canada’s most vulnerable areas to earthquake disasters.

== Sociological Considerations ==
Across disciplines, it is important that we realize our connectedness to one another and our reliance on one another to achieve what is best for our world. While Geology gives us the very foundation to understand how the ground we walk upon has formed and can change, Sociology gives us a way to figure out how to disseminate information to all parts of our communities and how we can support individuals across different living situations.

According to Costa et al. (2021), recent studies about the earthquake likelihood in Vancouver estimates that a 7.3 magnitude earthquake in the Strait of Georgia has 18% building damage and 12% collapse of buildings. Recovering from something like this? At least 2 years and up to 10 years! At least that is what data from according to other earthquakes that happened between 1980s-2020 (Costa et al., p. 47). Socioeconomic inequalities are likely to be further entrenched in the process and affect recovery, especially which regions in the city are prioritized for recovery resources and when (ibid.). Additional time is also consumed as homeowners make decisions about repairs, as governments and search for finances and skilled workers, and as repairs are conducted and initiatives to mitigate damage are brought from conception to fruition (Costa and Haukaas 2021).

Using the knowledge of Geology, Greater Vancouver's composition, and Sociological tools, we can begin to determine how ready we are for "the big one". In this section, we will explore three considerations of someone's livelihood and how it can be impacted by a large-scale earthquake: wealth disparities, access to housing, and access to healthcare services.
=== Wealth disparities of Vancouver ===
As Vancouver inches toward becoming a globally-renowned, large city with increasing infrastructure and a growing population, we have seen the divisions of wealth become quite stark. Unlike previous structures of society like feudalism which particularly differentiates "types" of people based on their proximity to nobility or aristocracy, today's society is built around an individual's proximity to wealth. Wealth is no longer necessarily an inheritance but also based on someone's intelligence, skills, and engagement with financial institutions, in the city or abroad. These pieces help define someone's '''class'''. Interpreting Sociologists Karl Marx and Friedrich Engels, Mattos (2022) explains that class categorization is not something that is assigned at birth but "[is] added to a repertoire of shared collective identification parameters" based on proximity to wealth and resources (pp. 9-10). Sociologists observe how class and the access, level, and success of interaction with certain institutions customize individuals' '''life chances'''. Consumption patterns, access to (accredited) education, housing, neighbourhood, and occupation (stability) all feed into one's social classification. For the purpose of this project specifically, we will explore how income is related to an individual's experience of earthquakes.

When the ground is shaking, how much money is in the bank or in your hands is likely not top of mind. However, in the event of an earthquake, someone's environment is highly impacted by their wealth. Neighbourhood, infrastructure, workplace, and school settings are all impacted by income. In their article on Canadian cities, Breau et al. (2017) explains that there is a spatial element to neighbourhoods that is affected by incomes of its residents and concludes that there is a slow polarization between higher income earners and lower income earners into distinguished neighbourhoods. Economic inequalities are also tethered to race and ethnicity. With Census data, Breau et al. (2017) find that in addition to loosing spatial ground, the Vancouver neighbourhoods subject to such urban reduction had higher visible minority and immigrant populations (p. 22). These two factors demonstrate a spatial segregation of lower income neighbourhoods. In combination with Vancouver's obvious practice of gentrification, lower income earners slowly find their neighbourhood retreated away from city centres, where most resources and services are situated (ibid., pp. 5-6).

For the case of Vancouver, Costa et al. (2021) explains that income for the richest neighbourhoods like Shaunnessy and West Point Grey is up to 4 times higher than poorer neighbourhoods like Strathcona and the West End (p. 49). Renter households make up the latter while the former is owner-occupied. Though an earthquake will not discriminate its impact, human systems' inherent inequalities can make some people more vulnerable than others. Building type, income, housing tenure, immigration status, and resource availability in the region are all pieces that will affect a person's proximity to earthquake impact and after effects. These factors will also be in relation to infrastructure in the area like workplaces and schools. After an earthquake, there becomes an inherent competition for resources for recovery among individuals and households. Costa et al. (2021) explains that the most profound challenge is distributing the available joint resources but accounting for their finiteness and scarcity in times of large-scale emergencies.

In the age of digitization, it can be easy to disseminate information about earthquake safety and alerts, as well as plans for recovery. However, not everyone has equal and constant access to technology and these means of communication. A large portion of this has to due with socioeconomic factors and largely due to income.

There is a level of uncertainty to the exact aftermath of something like a high-impact earthquake in Vancouver. We cannot be sure whether it will destroy homes, workplaces, families, or whether it will only be a minor blip in someone's professional and personal lived experience. However, in the hypothetical that the earthquake does severely affect areas of social and economic life of its residents, Vancouver must ensure that no one is left behind because of their class and income.
[[File:Couple Walk Past Homeless People on Sidewalk - Hastings & Main - Vancouver - BC - Canada (8602679460).jpg|alt=Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 but you may see the same sight in 2026 in the same area.|thumb|363x363px|Photographer captures a couple walking past two unhoused people on Main and Hastings in Vancouver, British Columbia. This photo was taken prior to 2014 and you will likely see the same sight of wealth disparity when you find yourself in that area today in 2026. In the event of a high magnitude earthquake (or really on any day), how can we make sure that no one gets left behind?]]

=== Housing in Greater Vancouver ===
The cost of living is a growing concern around the world and Vancouver is not an exception. It is, however, something that impacts certain classes of people more than others and the cost of living crisis is imminently tied to someone's access to long-term, stable housing.

For those who ''are'' housed, research on "Agent Based Models", which evaluates housing recovery after earthquake, gives us a way to figure out how we can plan for repairs and how much it will cost us. The object oriented model describes the recovery plan including building portfolio recovery, inspection, financing, permits, contractors, engineering firms, construction material suppliers, and power/transportation infrastructure (Costa et al. 2021). If there are an estimated 1200 inspections per day in just Metro Vancouver, you would need over 5000 permits and thousands of skilled workers for supporting crews and this is after the approvals and payments from insurance (6 weeks), private loans (15 weeks), and public loans (48 weeks) (ibid., p. 62). Transforming aggregate data into meaningful individual housing units can help plan for recovering, as illustrated in research presented by Costa et al. (2021).

Badal and Tesfamariam (2023) explain that the location of the building or house can impact its damage, likely referring to the geological composition of the land, its proximity to water bodies, and slope. Costa et al. (2021) explains that Downtown Vancouver is mostly made of new buildings while many homes in the West Side are from before 1975. There is also the case of places like East Vancouver which has a mix due to growing gentrification. Canadian Building code regulations on seismic safe construction began in1940 but was later revised in 1975, thus anything built before 1940 is unlikely to be seismic safe, and infrastructure between 1940-1975 have limited protection abilities (ibid., p. 49).

As we know, however, sociological considerations tell us that neighbourhoods based on class and income (Breau et al. 2017) also can impact the location and the quality of infrastructure. Vancouver has a growing unhoused community. It is important to note that someone couch surfing also is someone facing a form of homelessness but it obviously is to a different degree and quality than someone who relies on shelters or finds themselves without a roof of any kind on many days of their life. Earthquakes cause disruptions to transportation, power networks, water resources, economic growth and thus all ways of life! Seismic activity, geology, and social infrastructure impacted by earthquakes, and the aftermath of "the big one" all affect the unhoused in immense ways.

When it comes to the idea of disseminating information again, we are required to think of innovative ways of communicating with those who are unhoused. Mailing brochures is not an option and posting public service announcements on social media and other media sources is not accessible to everyone. Word of mouth and physical postering in unhoused community hubs and libraries. It is important to consider the way earthquakes will impact '''every''' person in the city, not just those who can present an address and a phone number. It requires a team of people who are especially careful of how this city can prepare to protect these folks in times of emergencies and times of re-building infrastructure. At the very most, every resident of the city should be housed, but at the very least, the city must do better at planning for safe spots or hubs for the unhoused in the case of a major earthquake and have a plan to bring them to safety.

=== Existing public health structures and crises ===

The COVID-19 Pandemic is remembered clearly for a variety of reasons and impacts, but most of all, the way it overwhelmed our healthcare system cannot be forgotten. Though an earthquake's health challenges will look different than that of a virus, it is true that the hospitals will be busy if damages are high. In the final moments after an earthquake, there may be some people in need of acute care, especially if they were hit by destroyed infrastructure or vehicles. Flooding, soil liquification, and broken building will also pose a risk for coming days.

It is more than just physical care that is needed after "the big one". Shiba et al. (2022) describes how post-disaster evacuation and displacement disrupts communities and social networks, changing a familiar environment into one that may be more self-isolating, especially if someone is living in other poor socioeconomic conditions prior to an earthquake. Cognitive impairment and social isolation therefore impact an individual's professional outlook and also impact cardio-metamobilc profiles and subjective wellbeing (ibid., p. 1). This can, in turn, affect an individual's self-nourishment. On the note of food, disaster and earthquake displacement is likely to increase the reliance on kitchen facilities which becomes an easier option for some rather than making home cooked meals (ibid.). These meals are unlikely to have have the healthiest nutrition profile and these facilities are already understaffed and underfunded. Lasty and the main focus of the research conducted by Shiba et al. (2022), is about persistent mental health issues, including some depressive and hopelessness profiles, due to being without their home and their eroded social capital. Counseling and other mental health supports are already difficult for many to access and this resource may experience further depletion after a large earthquake.

This is all considering that our hospitals are still in full working order! As mentioned previously, earthquakes do not discriminate and there is a high potential for hospitals and clinics to also face impacts to their infrastructure after seismic activities. Ceferino et al. (2019) explains that after an 8.0 magnitude earthquake, we can anticipate that about 51% of hospitals will have functioning operating rooms (p. 6). Again, it is impossible to fully presume that the same will apply to other areas such as Vancouver but we can work with this figure to plan for recovery, both in terms of where more operating rooms can be opened and the resources needed to bring hospital operation back to its full functioning capacity.

Canada is renowned for its free healthcare but not everything comes without a cost. For some, insurance is required and it stands behind a "Pay!" wall. For others such as our unhoused neighbours, they are in the most vulnerable positions for earthquakes and thus will likely need attentive care. Relating to the overall theme of this sociological considerations section, those who are in lower classes, unhoused, or make up part of the racial, ethic, or immigrant minorities are likely to face the brunt and most intersectional experiences. Precarious employment or housing and those who struggle on the low income side of the coin may also deal with issues with insurance. While Canadians are lucky that healthcare is virtually free, not everything is "covered" and not everyone is accounted for or can be taken care of in the systems we have in place. Figuring how we can look out for them and their wellbeing outside of disasters and "the big one" will make earthquake recovery plans more holistic and achievable when the time comes.

== So, are we ready for "the big one"? ==

=== When can we expect it? ===
Although its impossible to truly predict when "the Big One" will strike, geological evidence indicates that it is merely a matter of time rather than a hypothetical scenario. The Cascadia Subduction Zone has produced repeated mega-thrust earthquakes over thousands of years, with the most recent occurring on January 26, 1700, with an estimated magnitude of 8.7 to 9.2 (Pacific Northwest Seismic Network, n.d.). Geological evidence indicates that repeated great earthquakes over the past 10,000 years, with an average recurrence interval of about 500 years (Pacific Northwest Seismic Network, n.d.). Given that the recurrence of earthquakes is irregular and there remains no reliable method to predict the timing of an earthquake, scientists cannot predict exactly when the next major Cascadia earthquake will occur.

The occurrence of slow slip events along the Cascadia Subduction Zone does not eliminate the possibility of a future mega-thrust earthquake. Instead, these events release only a portion of the accumulated tectonic strain while stress continues to build on locked sections of the fault line (Frank, 2016). Consequently, Vancouver and other nearby communities must remain prepared for a major seismic event that occur at any time. Due to the likely outcome that "the Big One" is to produce intense ground shaking, widespread liquefaction in susceptible sediments, coastal subsidence, and tsunami hazards, continued monitoring, hazard mapping, and emergency preparedness remains essential for reducing future impacts.

=== Earthquake Preparedness ===

=== State and Community Support Networks ===

The Sociological considerations mentioned in the previous section tell us that Vancouver's population is diverse and hence the way in which we reach, communicate, and protect different groups of people must also be creative and unique. It also must mean that people across the wealth gradient are cared for equally, and prioritized equally when it comes to their built environments and overall wellbeing.

Vancouver lucky that there is so much geological and earthquake recovery research to draw upon when planning for "the big one". Since the 2000s, Performance Based Seismic Design (PBSD), a method that quantifies potential seismic events, have helped us figure out how we can estimate the effects of "the big one" (Badal and Tesfamariam 2023). Other models we can use are agent-based models as described in the previous section, hurricane recovery models based on socioeconomic demographics and recovery, and discrete-event simulation models looking at the availability of inspectors, loan officers, contractors (Costa et al. 2021). With these tools developed since the first anticipation of a high magnitude earthquake, Vancouver has been able to determine recovery plans. We know locations of buildings can impact the level of damage, there will be resource and skilled worker shortages, and repair times will take a long while. However, knowing this in advance gives us a way to plan for the future and plan well knowing these challenges.

It is important to mention that the community does a lot for one another already. Crowdfunding, mutual aid requests, and fundraisers are all ways that people of Vancouver show up for one another. However, in the face of high-impact seismic activity, or any natural disaster, communities need the support of the state as well. Though the method of organizing and the reach of the state and community initiatives differ, the state has a stronger way to centralize funding relief for its people and the costs to re-build infrastructure. It is imperative in times like these that the many units work collaboratively. Costa et al. (2021) and Badal and Tesfamariam (2023) corroborate that government funding for post-earthquake relief can help alleviate damage and accelerate recovery.

It will not be an individual effort to ensure recovery is achieved as quickly, thoroughly, and as unbiased as possible. When accounting for sociological inequalities, there ''is'' a way to plan for no one getting left behind.

==Conclusion==

==Author Information==
''KM, Sociology''

''Rishita Aporajita, Sociology''

''RG, Sociology''

This Wiki was created without the use of Artificial Intelligence. Each Section was produced and edited by the authors above. If further information is added by other users, we ask that they provide their name or initials in this section which breaks down whose writing is provided under the headings of the Wiki.

# Introduction (KM, RA, RG)
# Earthquakes (KM)
## Plate Tectonics
## Soil Composition and Liquefaction
## Impacts of Water on the coastline
# Vancouver (RG)
## Vancouver’s geology and proximity to fault lines
## Vancouver’s proneness to seismic activity
## Geological impacts of “the big one.”
# Sociological Considerations (RA)
## Wealth disparities of Vancouver
## Housing in Greater Vancouver
## Existing public health structures and crises
# Are we ready for “the big one”?
## When can we expect it? (KM)
## Earthquake preparedness (RG)
## Community Support Networks (RA)
# Conclusion of the research (KM, RA, RG)

==References==
<references />

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