Simulation of Tsunami Induced by Dynamic Displacement of Seabed due to Seismic Faulting

In conventional tsunami-simulation techniques, simplifications have been employed by neglecting the dynamic seabed displacement resulting from fracturing of a seismic fault and considering only the static contribution. The water layer is also assumed to be incompressible, regardless of its acoustic effects. They should be reconsidered in light of the state-of-the-art technology because considerable discrepancies between numerical simulations and actual observation have been pointed out regarding, for example, arrival time and wave height. In the present study, tsunami simulation is conducted without using these kinds of simplification, taking into account both the dynamic displacement and acoustic effects. As a result, thus simulated tsunamis are found to be remarkably larger in the wave height especially in the near-fault area where these two effects are superposed. In far-field, however, tsunamis thus simulated are likely to show little difference in the wave height, but show considerable difference in the arrival time. In addition, the present dynamic analysis is capable of simulating the water wave induced by the Rayleigh wave propagated along the seabed.