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Northwest Vancouver Island Tsunami Mapping survey

The Strathcona Regional District (SRD) and project partners are undertaking a Tsunami Flood Risk Assessment with assistance from Northwest Hydraulic Consultants (NHC) and Ocean Networks Canada (ONC). The goal of this project is to better understand tsunami risks on the northwest coast of Vancouver Island through tsunami models and the completion of a risk assessment with the integration of community experience and indigenous knowledge.

The study area expands south from Yuquot to Cape Scott to the north, and includes the communities of Gold River, Tahsis, Zeballos, and Port Alice, as well as several Indigenous communities including the Ka:’yu:’k’t’h’/Che:k:tles7et’h’, Nuchatlaht, Ehattesaht, Mowachaht / Muchalaht, and Quatsino First Nations (Figure 1). In addition to these locations, the study area covers the many historic community locations, sacred sites, fishing and hunting areas, shellfish harvesting sites and old village sites.

Figure 1 – Tsunami Risk Project Study Area and Communities

Why is it Important? 

  • Through sharing of experiences and knowledge we hope to help reduce tsunami risk in communities
  • Have a better understanding of what communities need for evacuation if necessary
  • Help to build community response and resiliency in extreme situations
  • Help the community understand where they can access emergency programs

Why Tsunami?   Introduction to Vancouver Island Tsunami Hazard

Northwest Vancouver Island is characterized by natural beauty and rich history. With the Pacific Ocean to the west, this region is exposed to tsunami hazard from local sources, such as the Cascadia Subduction Zone, and distant sources, such as the Aleutian Islands in Alaska. Other distant sources around the Pacific Ocean Ring of Fire could also affect Northwest Vancouver Island (Figure 2).

Even when communities are far from a tsunami source there can be impacts. Recent earthquakes that generated tsunamis in Japan and Indonesia have demonstrated this.

 

Figure 2 – Pacific Ocean Ring of Fire. Illustration adapted from Atwater et al. (2005)

Subduction zones are areas where tectonic plates meet, with one plate subducting (Figure 3). This process can build up enormous amounts of stress between the plates over time. When an earthquake occurs, this stress is released, causing the seafloor to lift and displacing the water above – this is how 90% of global tsunamis are generated.

Geological studies, historical records from Japan, and oral history from Indigenous communities along the west coast of North America show that the last large local tsunami was generated by a strong Cascadia earthquake which occurred on January 26th, 1700.

Scientific study of tsunamis on the west coast of Vancouver Island began in earnest in the 1980s, however, the history of tsunamis and the impacts of tsunamis is much longer. This is represented in several ways including the Nuu-chah-nulth story of mountain dwarves and the foot in drum legend (Figure 4). Along with other references, these accounts highlight the knowledge and teachings that exist with regards to earthquake and tsunamis on the west coast of Vancouver Island.

Figure 3 – Vertical Slice Through a Subduction Zone. Illustration adapted from U.S. Geological Survey (2005)

Figure 4 – Illustration by Nuu-chah-nulth artist Tim Paul of the earthquake foot in drum legend

How Can You Help?

Please help us by completing the survey and sharing your knowledge with our research team via:

Online Survey – see below

OR

Mailed Survey – Please drop off completed surveys at the following locations:

  • Nuchatlaht First Nation office
  • Village of Gold River office (front door drop slot)
  • Village of Port Alice office
  • Village of Tahsis office (outside dropbox)
  • Village of Zeballos office

Pre-paid return postage can be requested by contacting Shaun Koopman at preparedness@srd.ca or 250-830-6702.

Please provide your feedback by 4pm on Friday February 26th, 2021.