祝爱玉^1,2,3,,
王永哲^1,2,3,,,
李永华^1,2,3,
张东宁^1,2
1. 中国地震局地球物理研究所, 北京 100081
2. 北京白家疃地球科学国家野外科学观测研究站, 北京 100095
3. 中国地震局震源物理重点实验室, 北京 100095

基金项目: 国家科技部重点研发课题（2018YFC1503200）和中国地震局地球物理研究所基本业务费（DQJB19A0124，DQJB20B18）的共同资助


详细信息

作者简介: 祝爱玉, 女, 1979年生, 副研究员, 从事地球动力学数值模拟方面科研工作.E-mail: aiyuzhu@cea-igp.ac.cn

通讯作者: 王永哲, E-mail: yzwang@cea-igp.ac.cn

中图分类号: P315

收稿日期:2021-06-30
修回日期:2021-08-31
上线日期:2021-12-10

Numerical simulation on the mechanism of the Madoi, Qinghai M_S7.4 earthquake constrained by InSAR deformation

ZHU AiYu^1,2,3,,
WANG YongZhe^1,2,3,,,
LI YongHua^1,2,3,
ZHANG DongNing^1,2
1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2. Beijing Baijiatuan Earth Science National Observation and Research Station, Beijing 100095, China
3. KeyLaboratory of Earthquake Source Physics, China Earthquake Administration, Beijing 100095, China


More Information

Corresponding author: WANG YongZhe,E-mail:yzwang@cea-igp.ac.cn

MSC: P315

--> Received Date: 30 June 2021
Revised Date: 31 August 2021
Available Online: 10 December 2021


摘要
摘要:2021年5月22日在青海玛多发生M_S7.4地震，此次地震造成了严重的地表破坏.本文通过合成孔径雷达干涉测量（InSAR）技术得到了Sentinel-1升、降轨同震地表形变、东西方向和垂直方向的同震形变场.并根据东西向地表的错动，勾画出了地震破裂面分段结构.以InSAR地表形变观测为约束，构建了能反映玛多地震破裂特点的三维黏弹性有限元模型，模拟得到了玛多地震的三维同震形变及应力场变化和演化特征，讨论了玛多地震的成因及玛多地震的发生对周边断层的影响.结果显示：玛多地震为典型的左旋走滑型地震，其中东部错动量相对较大；玛多地震的余震都分布在库仑应力升高的影区，说明玛多地震序列使得断层上积累的应变得到了充分的释放，未来余震的发生会朝西南和东北方向发展.玛多地震的发生形成了多个应力强加载区，推测玛多地震的发生大大增加了部分临近断裂带滑动的可能.2010年玉树7.3级地震引起的库仑应力变化在玛多地震主破裂面上的投影为正数，推测玉树地震对玛多地震具有促进作用.研究结果可以为大震后的余震分布判断提供定量参考依据.
关键词: 玛多地震/
同震位移/
库仑应力变化/
InSAR形变观测/
数值模拟

Abstract:The Madoi M_S7.4 earthquake occurred in Qinghai Province on 22 May 2021, which caused serious damage on the surface. In this work, using the interferometric synthetic aperture radar (InSAR) technology, coseismic surface deformation in ascending and descending directions of Sentinel-1, east-west and vertical directions were obtained, and the segmented structure of earthquake rupture surface was delineated. Constrained by the observed surface deformation from InSAR, a 3D viscoelastic finite element model considering the rupture characteristics of the Madoi earthquake was constructed. Then the 3D coseismic deformation and stress field of the Madoi earthquake were simulated. Results show that the Madoi earthquake is a typical left-lateral strike-slip faulting, in which the fault slip in the east is relatively large. The aftershocks of the Madoi earthquake are all distributed in the area where the Coulomb stress variation is negative, which indicates that the Madoi earthquake has fully released the accumulated strain on the fault and the occurrence of aftershocks in the future will spread towards the southwest and northeast. The occurrence of the Madoi earthquake has formed several stress enhancement areas, which indicates that the Madoi event has greatly increased the possibility of sliding of some other fault zones. The projection of Coulomb stress variation caused by the 2010 Yushu M7.3 earthquake on the main rupture surface of the Madoi earthquake is positive, which permits to speculate that the Yushu earthquake may have promoted the Madoi shock. This study can provide a quantitative reference for the judgment of aftershocks and possible surface damage following big earthquakes.
Key words:Madoi earthquake/
Coseismic displacement/
Coulomb stress variation/
InSAR deformation observation/
Numerical simulation



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