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Title:: Characteristics of InSAR Coseismic Deformation and Slip Distribution of the Akto M_S6.7 Earthquake,Xinjiang

作者:: 邱江涛¹; 2; 赵强¹; 林鹏¹; (1.中国地震局第二监测中心,陕西西安 710054; 2中国地震局地震研究所,湖北武汉 430071)

Author(s):: QIU Jiangtao¹; 2; ZHAO Qiang¹; LIN Peng¹; (1.The Second Monitoring and Application Center,China Earthquake Administration,Shannxi 710054,Xi'an,China)(2.Institute of Seismology,China Earthquake Administration,Wuhan 430071,Hubei,China)

Keywords:: the Akto earthquake; InSAR; coseismic slip distribution; Muji fault; focal mechanism

摘要:: 2016年11月25日新疆阿克陶M_S6.7地震发生在帕米尔构造结的弧顶地区、木吉断陷盆地西端附近,此次地震主震破裂过程复杂,根据地震波反演确定的震源机制解也存在较大差异。利用InSAR技术处理Sentinel-1 SAR影像数据获取了此次地震的同震形变场,基于弹性半空间位错模型,确定了断层几何参数和滑动分布模型。结果表明,分布式滑动模型能较好地解释观测到的InSAR地表形变场。本次地震包括了至少2次破裂子事件,分别位于中国地震台网测定的震中以东约7 km处(74.11°E,39.25°N)、以东约33 km处(74.49°E,39.16°N)。地震引起的形变场呈上下对称性分布,最大LOS向形变量为20 cm。地震同震位错以右旋走滑为主,主要的滑动量集中在地下深度0～20 km处,最大滑动量为0.84 m。发震断层为木吉断裂,此次地震显示印度板块的北东向推挤作用在增强。

Abstract:: The Akto M_S6.7 earthquake,Xinjiang occurred near the western end of the Muji fault basin in the top of the Pamir syntax.The main shock of this earthquake is complicated and the focal mechanism solutions show differences based on seismic wave inversions.Based on the Sentinel-1 SAR image data,the coseismic deformation field of the earthquake is obtained by InSAR technique.Based on the elastic half-space dislocation model,the geometrical parameters and the slip distribution model are determined by nonlinear and linear inversion algorithms.The results show that the distributed slip model can well explain the coseismic deformation field.The earthquake includes at least two rupture events,which are located at 7 km(74.11 ° E,39.25 ° N)and 33 km(74.49 ° E,39.16 ° N)east of the epicenter of the CENC.The deformation field caused by the earthquake shows symmetric distributions,with the maximum deformation(LOS)of 20 cm.The main seismic slip is concentrated in the 0～20 km depth,and the maximum slip is 0.84 m.The seismic fault is the Muji fault,and this earthquake shows that the N-E thrust of the Indian plate is enhanced.