1995年兵庫県南部地震の複数アスペリティモデルの提案とそれによる強震動シミュレーション

抄録

We simulate strong motions in Kobe during the Hyogo-ken Nanbu (Kobe) earthquake of 1995 using a multiple asperity source model and a three-dimensional (3-D) basin structure. We derive a relatively simple rupture process, which consists of four asperities, using theoretical synthetics so that it matches the deconvolved bedrock motion at JMA Kobe. A realistic 3-D basin structure is constructed based on the exploration data. A 3-D finite difference method with fourth ordered staggered-grid scheme developed by Graves (1996) is used. The results show that with the combination of a relatively simple four asperity model and a 3-D basin structure, it is possible to reproduce strong ground motions in a wide area quite accurately. Peak velocity distribution is very similar to the JMA intensity distribution. From these results we confirm that we can reproduce strong ground motion in Kobe quite quantitatively by using a relatively simple source model that efficiently generate 1 second velocity pulses, together with a realistic 3-D basin structure.