The reference point of the scale bar is assumed to be the bottom left corner of the map. The black line and white arrows depict the location of the trench the orange triangles show the points used to drive the maximum subsidence. 1100 km, likely rupturing the entire zone ( Satake, 2003).įigure 1The domain of interest. The moment magnitude ( M w) of the earthquake was estimated close to 9, with a rupture length of ca. The most recent megathrust earthquake in the Cascadia subduction zone was the 1700 earthquake, the timing of which was inferred from records of an orphan tsunami in Japan ( Satake et al., 1996 Satake, 2003). A sequence of great earthquakes has been inferred for the region over the last ∼6500 years with an average interval rate of 500–600 years (individual intervals may vary from a few hundred to 1000 years) ( Atwater and Hemphill-Haley, 1997 Clague et al., 2000 Goldfinger et al., 2003, 2012). Historical and geological records show that great plate boundary earthquakes were responsible for large-tsunami events in the past ( Clague et al., 2000 Goldfinger et al., 2012). Earthquake-induced tsunamis generated from the Cascadia subduction zone pose an imminent threat for the west coasts of the United States and Canada but also other coastal regions in the Pacific Ocean. The zone lies on the interface of the subducting oceanic plate of Juan de Fuca and the overriding lithospheric plate of North America. The Cascadia subduction zone is a long subduction zone that expands for more than 1000 km along the Pacific coast of North America, from Vancouver Island in the north to northern California in the south (Fig. This approach allows for the first emulation-accelerated computation of probabilistic tsunami hazard in the region of the city of Victoria, British Columbia. The low cost of emulation provides for additional flexibility in the shape of the deformation, which we illustrate here considering two families – buried rupture and splay-faulting – of 2000 potential scenarios. We implement an advanced sequential design algorithm for the optimal selection of only 60 simulations. uplift/subsidence ratio and maximum uplift, that represent the seabed deformation. We train the emulators on a set of input–output pairs and use them to generate approximate output values over a six-dimensional scenario parameter space, e.g.
The emulators are statistical approximations of the simulator's behaviour.
#Download shuttle sequentially simulator#
We replace the simulator by a Gaussian process emulator at each output location to overcome the large computational burden. We use the graphics processing unit (GPU)-accelerated tsunami simulator VOLNA-OP2 with a detailed representation of topographic and bathymetric features. Previous probabilistic tsunami hazard assessment studies produced hazard curves based on simulated predictions of tsunami waves, either at low resolution or at high resolution for a local area or under limited ranges of scenarios or at a high computational cost to generate hundreds of scenarios at high resolution. The potential of a full-margin rupture along the Cascadia subduction zone poses a significant threat over a populous region of North America.
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