著者
古村 孝志
出版者
公益社団法人 東京地学協会
雑誌
地学雑誌 (ISSN:0022135X)
巻号頁・発行日
vol.123, no.4, pp.434-450, 2014-08-25 (Released:2014-09-01)
参考文献数
28
被引用文献数
2 2

In the Kanto basin, long-period (T = 6-8s) ground motions develop during large (M > 7) earthquakes due to the resonance of surface waves with thick (> 3000m) sedimentary layers covering rigid bedrock. Such long-period ground motions can cause significant damage to modern large-scale, long natural-period structures such as skyscrapers, oil storage tanks, and long bridges. Therefore, it is important that residents of modern Tokyo metropolitan area cities be forewarned about the potential for such disasters. In the present paper, the development of large and long-duration, long-period ground motions in central Tokyo is investigated by analyzing waveform data from recent large earthquakes obtained from dense seismic networks extending over the Kanto basin. It is demonstrated that the interaction of surface waves with the three-dimensional sedimentary structure beneath the Kanto region causes peculiar and directional dependencies related to the amplification strength of the long-period ground motions. For example, the long-period ground motions resulting from earthquakes occurring in northern Japan cannot develop efficiently in central Tokyo. This might be one reason for the relatively weak long-period ground motions observed in central Tokyo during the 2011 Off Tohoku M 9.0 earthquake compared to those of other M 7-8 class events, such as the 1944 Tonankai (M 7.9) and the 2003 Off Tokachi (M 8.0) earthquakes. The results of computer simulations using detailed subsurface structures and source-slip models for an anticipated Nankai Trough M 8.7 earthquake indicates that the strength of long-period ground motions in central Tokyo can be expected to be at least double than those observed during the 2011 Off Tohoku earthquake.

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古村孝志, 2014, 関東平野の深部基盤構造と長周期地震動リスク. 地学雑誌, vol. 123 (4), p. 434-450 https://www.jstage.jst.go.jp/article/jgeography/123/4/123_123.434/_article/-char/ja/

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昨年出たばかりの論文見つけた。 古村孝志先生の。 関東平野の深部基盤構造と長周期地震動リスク https://t.co/pQT5ykui7Z 地殻構造も大事だけど、関東平野の特に都市部に住む人間にとっては基盤構造の知識も知らないよりは知っていたほうが良いと思われ。
古村孝志, 2014, 関東平野の深部基盤構造と長周期地震動リスク. 地学雑誌, vol. 123 (4), p. 434-450... http://t.co/mAJoK0MCbh

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