福岡市における三次元地下構造を考慮したハイブリッド法による広周期帯域強震動予測

概要

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We estimate broadband strong ground motions in Fukuoka City by using a three-dimensional (3-D) basin structure. First, we simulate strong ground motions during the Hyogo-Ken Nanbu earthquake of 1995 using a hybrid simulation technique, in which we combine a semi-empirical method and a 3-D finite difference method. We confirm that we can reproduce broadband strong motions in Kobe City using our hybrid simulation technique. Since the 3-D basin structure of Fukuoka City has not been estimated yet, we estimate the 3-D basin structure below Fukuoka City by using a geological map and a gravity anomaly map, together with S-wave velocity structures at several points inside the basin. Finally we use our hybrid simulation technique to estimate broadband strong motions in Fukuoka City for hypothesized scenario earthquakes. The result of our simulation shows that we have to prepare for a severe disaster in the center of Fukuoka City, once such an event would occur. For more quantitative simulation we need to introduce soil non-linearity.
2002-10-30