Modelling Large Tsunamis Generated by Cascadia Subduction Zone Earthquakes

Tsunami Model

Numerical model MOST3 (Method of Splitting Tsunamis, version 3) computes generation, propagation and runup of tsunami waves and currents (Titov and Synolakis, 1995, 1996, 1997). Wave propagation is accomplished with a numerical dispersion scheme and non-linear shallow-water wave equations in spherical coordinates. We present here the results from numerical experiments designed to compute waves and currents in Victoria and Esquimalt Harbours after a large Cascadia earthquake.

Three nested grids are used in the model and are shown as following:

NX NY Latitude range Longitude range
A 351 700 43.000-50.000N 122.000-129.999W
B 870 900 47.750-49.250N 122.100-125.000W
C 1200 675 48.400-48.461N 123.368-123.476W

Each finer grid communicates with a coarser grid through common open boundaries. The model was designed to compute shoreline wetting (wave runup) and drying (wave retreat) in its finest grid (C), which in our case has a grid size of about 10m.

Model Results

Disclaimer : These are preliminary results that have not been officially published and should not be used as a basis for engineering design and policy.

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