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中国科学院大学学报 ›› 2017, Vol. 34 ›› Issue (1): 86-98.DOI: 10.7523/j.issn.2095-6134.2017.01.012

• 地球科学 • 上一篇    下一篇

2004年Mw9.3苏门答腊地震产生的库仑应力

瞿武林, 张贝, 黄禄渊, 程惠红, 张怀, 石耀霖   

  1. 中国科学院大学 中国科学院计算地球动力学重点实验室, 北京 100049
  • 收稿日期:2016-03-07 修回日期:2016-04-28 发布日期:2017-01-15
  • 通讯作者: 石耀霖,E-mail:shiyl@ucas.ac.cn
  • 基金资助:

    国家自然科学基金重大项目(41086965)与中国科学院国际合作创新团队项目(KZZD-EW-TZ-19)资助

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 Published:2017-01-15

摘要:

2004年12月26日苏门答腊Mw9.3地震产生的应力扰动,强烈影响了苏门答腊及其周边地区的地震活动性,甚至对中国西南部地区的地震活动性也有明显的影响。基于断层滑动模型,采用等效体力处理断层错动有限单元方法,分别用分层球对称地球模型与三维横向不均匀性地球模型计算在全球地壳和地幔中产生的同震效应。据此,对在苏门答腊和中国西南等地区产生的同震效应进行重点分析。结果表明:在同震破裂面附近,使用三维不均匀性地球模型与使用分层球对称模型得到的结果有明显差别,前者更加合理。在同震破裂面附近有必要使用三维不均匀性地球模型。使用球对称模型计算,有67.6%的余震发生在库仑应力增加区;而使用横向不均匀性地球模型时,计算的这一比率可高达72.3%,这说明余震与断层库仑应力增加区域有很好的对应关系。在西安达曼断层北段余震的发生与库仑应力为正值的主要断层有很好的对应关系,余震受到其附近的主要断层的控制作用。

关键词: 2004年苏门答腊地震, 有限元方法, 三维横向不均匀性, 库仑应力, 地震触发

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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