The Cascadia Subduction Zone fault is a 1,000-km-long dipping fault that stretches from Vancouver Island, British Columbia to Cape Mendocino, California. It separates the Juan de Fuca and North American plates. The Juan de Fuca plate moves toward and eventually is pushed beneath the North American plate. When energy is released from these plates, a megathrust earthquake is expected to occur, generating a tsunami. The last known megathrust earthquake on this fault was in January 1700, with an estimated magnitude of 8.7 to 9.2. A tsunami generated by a megathrust earthquake will inundate First Nation communities along the west coast of Vancouver Island. The combination of sea-level rise and tsunami will increase the extent of inundation. Parsons was retained by Indigenous Services Canada to deliver a multi-year project to model tsunami and storm surge inundation and to identify critical at-risk infrastructure within the communities.
Parsons collected climate and sea-level rise data and also local community infrastructure information, and conducted topographic and bathymetric surveys during visits to the communities. These data were analyzed and incorporated into the model. We then developed high-density finite element models for each community for both tsunami and storm events including sea-level rise to estimate the extent of inundation for each community.
The presentation will discuss how this modeling technique has led to the development of innovative approaches to visualizing flooding from tsunamis, storms, and sea-level rise.