Integrated Ground Motion and Tsunami Simulation for the 1944 Tonankai Earthquake Using High-Performance Supercomputers

Abstract

An integrated simulation of seismic wave and tsunami has been developed for mitigation of earthquake and tsunami disasters associated with large subduction-zone earthquakes occurring in the Nankai Trough. The ground motion due to the earthquake is firstly calculated by solving equation of motions with heterogeneous source-rupture model and 3-D heterogeneous subsurface structural model. Tsunami generation and propagation in heterogeneous bathymetry is then simulated by solving the 3-D Navier-Stokes equation. Ground motion and tsunami simulations are combined through an appropriate dynamic boundary condition at the sea floor. Thanks to supercomputers and efficient parallel computing, we are reproducing strong ground motion and tsunamis caused by the M8.0 Tonankai earthquake in the Nankai Trough in 1944. The visualized seismic wavefield and tsunami derived by integrated simulation provides a direct understanding of disasters associated with Nankai Trough earthquakes with the development of long-period ground motion in highly populated basins such as Tokyo, Osaka, and Nagoya and tsunamis striking along Japan’s Pacific Ocean coast.