統計的グリーン関数法による1993年北海道南西沖地震の震源域を含む広域における地震動シミュレーション : 強震動予測のための震源モデルの特性化手法の検証

Abstract

We simulated strong ground motions during the 1993 Hokkaido-Nansei-Oki, Japan, earthquake (MJMA 7.8) based on its variable-slip rupture model and on two types of characterized asperity models to verify the characterizing procedure of source models for the strong motion prediction in future earthquakes. The asperity models were characterized by the total seismic moment, the short-period level of the source spectra, and the ratios of the area, the slip amount, and the effective stress on the asperity to those on the entire fault. The stochastic Green's function method was applied to the wide area including the epicentral region, and the following results were obtained : 1) The asperity model whose asperity was arranged at the shallow position according to the final slip distribution of the variable-slip rupture model produced a little larger ground motions than the variable-slip rupture model did. 2) On the other hand, the asperity model whose asperity was arranged at the deep position according to the short-period level distribution of the variable-slip rupture model produced the same ground motions as the variable-slip rupture model did.