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›› 2017, Vol. 34 ›› Issue (1): 86-98.DOI: 10.7523/j.issn.2095-6134.2017.01.012

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Coulomb stresses induced by the 2004 Mw9.3 Sumatra earthquake

QU Wulin, ZHANG Bei, HUANG Luyuan, CHENG Huihong, ZHANG Huai, SHI Yaolin   

  1. Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-03-07 Revised:2016-04-28 Online:2017-01-15

Abstract:

The stress perturbation induced by 2004 Sumatra earthquake has greatly changed seismicity around Sumatra and its vicinity, including Southwest China. In this study, we calculated the co-seismic stress changes induced by this earthquake using a layered spherically symmetric earth model and a 3D laterally heterogeneous earth model. Both the calculations are based on the fault slip model, which fits well with the GPS observation and has been widely quoted by other researchers, and the equivalent body force finite element method is applied to deal with the co-seismic fault slip effect. The entire volume of a spherical shell from earth surface to core-mantle boundary is included in our investigation, and boundary conditions can be easily assigned to the two boundaries. In the spherical symmetric model, there are 67.6% of aftershocks occurring in regions of positive Coulomb stresses. In the lateral heterogeneous model, 72.3% of aftershocks occurring in regions of positive Coulomb stresss. The aftershocks in the northern part of west Andaman fault have good correlation with the main faults which have positive Coulomb stress. So the aftershocks were apparently controlled by adjacent main faults.

Key words: 2004 Sumatra earthquake, finite element method, 3D lateral heterogeneity, Coulomb stress, earthquake triggering

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