2015年西藏定日M_(W)5.7地震震源参数估计和静态应力触发研究  

Research on the Seismic Source Model and Static Stress Triggering of the 2015 Dingri M_(W)5.7 Earthquake

作　　者：方金玲 赵斌[1,2] 余建胜[1,2] 陈威[1] FANG Jinling;ZHAO Bin;YUJiansheng;CHEN Wei(Institute of Seismology,CEA,40 Hongshance Road,Wuhan 430071,China;KeyLaboratory of Earthquake Geodesy,Institute of Seismology,CEA,40 Hongshance Road,Wuhan430071,China)

机构地区：[1]中国地震局地震研究所,武汉市430071 [2]中国地震局地震研究所地震大地测量重点实验室,武汉市430071

出　　处：《大地测量与地球动力学》2022年第9期964-970,共7页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42074116,42074015);湖北省自然科学基金(2021CFB508)。

摘　　要：采用InSAR形变监测资料计算2015年西藏定日M_(W)5.7地震同震形变场,反演发震断层几何参数和滑动分布。在此基础上,研究尼泊尔M_(W)7.8主震对定日地震的静态库仑应力触发影响。综合分析地震滑动机制和构造特征,认为定日断层为西倾隐伏断层。反演结果表明,地震破裂相对集中,主要深度在6~9 km,破裂以正断滑动为主。发震断层走向约178°,倾角约48°,破裂区长约5 km,宽约5 km,最大滑动量约0.2 m,释放的地震矩约3.7×10^(17) N·m,对应矩震级M_(W)5.6。尼泊尔主震同震库仑应力在定日地震震源处约为0.2 bar,造成藏南申扎-定结拉张地堑应变加载。Using the InSAR deformation monitoring data,we calculate the coseismic deformation field of the Dingri M_(W)5.7 earthquake in Tibet in 2015,and inverse the geometric parameters and slip distribution of seismogenic faults.Then,we analyze the static Coulomb stress triggering effect of the Nepal M_(W)7.8 main earthquake on Dingri earthquake.Based on the comprehensive analysis of seismic slip mechanism and structural characteristics,we consider that Dingri fault is a buried west-dipping fault.The inversion results show that the rupture is relatively concentrated and mainly distributed in the depth range of 6~9 km with a predominantly normal fault mechanism.The strike and dip of the seismogenic fault of Dingri earthquake are about 178°and 48°,respectively.The length and width of the rupture zones are approximately 5 km and 5 km,respectively,and the maximum slip is about 0.2 m.The released seismic moment is estimated to be about 3.7×10^(17) N·m,corresponding to a magnitude of M_(W)5.6.The coseismic Coulomb stress of Nepal earthquake is about 0.2 bar at the focal point of the Dingri earthquake;it caused the strain loading of the Xainza-Dinggye rift in southern Tibet.

关 键 词：定日地震 InSAR同震形变 滑动分布反演 尼泊尔地震 库仑应力 

分 类 号：P315[天文地球—地震学]