Tsunami evacuation simulation for the District of Tofino, Vancouver Island, Canada

A large earthquake event generated from the nearby Cascadia Subduction Zone would possibly generate a significant tsunami event which could affect the west coast of Canada. In this study, to critically assess the effects of a tsunami on the District of Tofino on Vancouver Island, British Columbia, tsunami simulations were performed. As a result of tsunami propagation and inundation simulations, it was found that for earthquakes Mw9.0 or greater, the central part of the Esowista Peninsula on which Tofino is located will be completely inundated. The authors have also conducted tsunami evacuation simulations using an agent-based model developed by Takabatake et al. (2017). This evacuation model considered Tofino's large fluctuation in residents due to seasonal tourism in a number of selected scenarios. Using the model, the authors also conducted a sensitivity analysis to investigate effects of the change in evacuation behaviour on the mortality rate. The results showed that a significant number of casualties would occur in Tofino, especially if an earthquake was to occur at night. It was also shown to be important to consider the capacity of evacuation buildings when directing evacuees, especially the elderly. In addition, the present study clarified that the effects of evacuation start time and route choices on the mortality rate would vary significantly according to a population distribution scenario even in the same study area. It was thus highlighted that conducting sensitivity analysis under varied population distribution scenarios is important to understand properly the uncertainty associated with tsunami evacuation.