Effects of Earth’s curvature and radial heterogeneity in dislocation studies: Case studies of the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake
Effects of Earth’s curvature and radial heterogeneity in dislocation studies: Case studies of the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake
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DOI：
10.1007/s11589-010-0727-5
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发表时间：
2010-08
影响因子：
1.2
通讯作者：
G. Fu;Wenke Sun;Y. Fukuda;Shanghua Gao;T. Hasegawa
中科院分区：
文献类型：
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作者：
G. Fu;Wenke Sun;Y. Fukuda;Shanghua Gao;T. Hasegawa
近年来，以2004年苏门答腊地震为例，研究了地球曲率和径向不均匀性对同震形变的影响。然而，这种影响与地震类型密切相关。2004年苏门答腊地震作为一个低倾角地震，由于中等倾角地震的影响要大得多，因此不是一个很好的地震案例。本文分别采用半空间位错理论和球面位错理论计算了2008年汶川地震和2004年苏门答腊地震的同震位移。通过两种位错理论计算结果的差异，研究了地球曲率和层结的影响。结果表明，2008年汶川地震的地球曲率和分层效应远大于2004年苏门答腊地震。对于2008年汶川地震这样的中等倾角地震，忽略这些影响将导致远场位移误差高达100%-200%。这种巨大的影响远远大于以往研究的结论。此外，通过与观测结果的比较，证实了球位错理论在远场的计算结果优于半空间理论。
Recently, effects of Earth’s curvature and radial heterogeneity on coseismic deformations are often investigated based on the 2004 Sumatra earthquake. However, such effects are strongly related to earthquake types. As a low dip angle event, the 2004 Sumatra earthquake is not a good seismic case for such a topic since the effects for moderate dip angle events are much bigger. In this study, the half-space and spherical dislocation theories are used, respectively, to calculate coseismic displacements caused by the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake. Effects of Earth’s curvature and stratification are investigated through the discrepancies of results calculated using the two dislocation theories. Results show that the effects of Earth’s curvature and stratification for the 2008 Wenchuan earthquake are much larger than those for the 2004 Sumatra earthquake. Ignoring the effects will cause errors up to 100%–200% in far field displacements for a moderate dip angle event like the 2008 Wenchuan earthquake. Such great effects are much bigger than those conclusions of previous studies. Besides, comparison with observations verifies that spherical dislocation theories yield better results than half-space ones in far fields.