Kawaji, Kaoru

Tsunami Simulation Using Computed Ground Motion of the 2011 Tohoku Earthquake

Abstract eng:
A tsunami simulation is carried out using seabed displacement as initial tsunami-water level, which is obtained from a ground-motion simulation for the 2011 Tohoku Earthquake. First, a large scale ground-motion simulation is performed for the whole Eastern Japan with a voxel type finite-element method. Two types of seismic source model are adopted in the ground-motion simulation. One is derived from an inversion analysis based on teleseismic data, the other is derived on strong-motion data. Simulated ground-motion waveforms generally correspond to the observed ones at K-NET and KiK-net stations in the Eastern Japan. Second, a tsunami simulation is executed by a finite-difference method based on the shallowwater theory. Simulated tsunami waveforms are roughly consistent with observed ones of GPS wave gauges deployed off the Pacific coast of Tohoku. Coastal tsunami heights in the Sendai Plain and inundation around the Soma Port simulated by the source models based on the teleseismic and the strong-motion data are well consistent with observed ones, because large slips are generated on deep part of the fault plane in both models appropriately. However, the tsunami heights in the Sanriku coast simulated by the source model based on the teleseismic data are fairly lower than the observed heights, because the slip near the Japan Trench in this model is not so large. On the other hand, the simulated heights based on the strong-motion data correspond with the observed ones, because there is a huge slip near the trench axis in this model. A large slip on shallow part of the fault plane near the trench axis, which affects large tsunami heights in the Sanriku coast, is hard to be detected by the seismic observation, because of lack of strong ground-shaking in its observation. It is desirable to reproduce the large slip near the trench axis by the weak ground-shaking caught in the teleseismic or the strong-motion observation with higher accuracy.

Contributors:

Korenaga, Mariko

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.