My group’s project focused on earthquake danger zones in the greater Vancouver area, specifically on which hospitals are at risk to moderate to high liquefaction during a Cascadia Subduction Zone earthquake, and how they should be mitigated for. The last major Cascadia Subduction Zone earthquake was in 1700 with an estimated magnitude of 8.7-9.2 and was also correlated to a tsunami inferred from Japanese records. Evidence of this megathrust earthquake can be found in tree rings and sediment layers along the coast of the Pacific Northwest. According to Cascadia Region Earthquake Workgroup, the evidence for past earthquakes of magnitude 9.0 suggests that they recur on average every 500 years, but the actual intervals between events are far from predictable – such earthquakes have been separated by as many as 1,000 years and as few as 200.
Unfortunately, we cannot predict the exact moment of a Cascadia Subduction Zone earthquake, but we can prepare for the possible outcomes to ensure the safety and health of greater Vancouver’s population. To start, my group looked at the surficial geology of the greater Vancouver area and categorized the potential liquefaction of the different sediments into nil (no risk), low risk, and moderate to high risk. After intersecting our surficial danger zone layer with the 2011 census data of greater Vancouver, we discovered 39% of the population lives in moderate to high risk areas, 56.6% of the population lives in low risk areas, and 3.8% of the population lives in bedrock areas, which we categorized as ‘nil’.
We then intersected our Health Facilities layer, containing all the hospitals in the greater Vancouver area, with our surficial danger zone layer to find which hospitals are located in the moderate to high risk liquefaction area. We discovered four hospitals located in the cities of Richmond, Delta, White Rock, and Surrey are in moderate to high risk areas. These areas are of most concern and are to be subjected to high mitigation efforts compared to other cities. We looked at the number of beds that each hospital contains and how current patients and injured citizens during an event of a Cascadia Subduction Zone Earthquake should be transported to other hospitals in neighboring ‘nil’ or low risk areas.
Overall, I learned about time management, communication, and patience during this group project. My group members were very good about planning and meeting to discuss and work on our project, and doing our own parts of the essay outside our meeting times.
I solidified my knowledge of intersecting, overlaying, and joining tables and layers by performing these tasks countless times throughout the making of our two maps. I learned how to create symbols that vary in size to represent different values, we used this while plotting hospitals with differing sizes due to the amount of beds each hospital contains. I feel more confident in my abilities to create maps from scratch by researching the data, downloading, converting using ArcCatalog, uploading to ArcMap, clipping layers, etc. I look forward to taking additional GIS courses and potentially making a career by joining GIS with my interests in biogeography and climate change.
