深部不整形地下構造を考慮した神戸市の地震動の増幅特性解析 : 兵庫県南部地震における「震災の帯」の解釈

概要

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To estimate the amplification characteristics of the ground motions in the heavily damaged belt zone in Kobe City during the 1995 Hyogo-ken Nanbu earthquake, 3-D wave propagation analyses of a 2-D deep irregular underground structure model with vertical discontinuity were performed using the hyperelement method for incident plane waves expected from the wavefields due to the source mechanism. The incident waveform at bedrock is evaluated by deconvolution analysis using the observation record at Kobe University. The ground motion at the surface of the Osaka group layers and at ground surface are calculated. The effects of the deep irregular underground structure and shallow surface layers on the ground motion amplification are discussed. The analytical results show that the ground motions in the heavily damaged belt zone were amplified due to the focusing effect in the deep irregular underground structure as well as the shallow surface layers, and that the calculated maximum acceleration distributions coincide closely with the distribution of structural damage.
1996-10-30