杂多Mw 5.9级地震断层滑动的InSAR反演及边界元分析  

InSAR Inversion and Boundary Element Analysis of the Zadoi Mw 5.9 Earthquake Fault Slip

作　　者：刘洋[1,2,3] 许才军 温扬茂[1,2,3] 李志才 LIU Yang;XU Caijun;WEN Yangmao;LI Zhicai(School of Geodesy and Geomatics,Wuhan University,Wuhan 430079,China;Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University,Wuhan 430079,China;Collaborative Innovation Center of Geospatial Technology,Wuhan 430079,China;Department of Geodesy,National Geomatics Center of China,Beijing 100048,China)

机构地区：[1]武汉大学测绘学院,湖北武汉430079 [2]武汉大学地球空间环境与大地测量教育部重点实验室,湖北武汉430079 [3]地球空间信息技术协同创新中心,湖北武汉430079 [4]国家基础地理信息中心大地测量部,北京100048

出　　处：《武汉大学学报（信息科学版）》2020年第11期1678-1686,共9页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(41874011,41774011,41861134009);国家重点研发计划(2018YFC1503603)。

摘　　要：利用合成孔径雷达干涉测量(interferometric synthetic aperture radar,InSAR)技术和哨兵1号卫星升轨、降轨合成孔径雷达数据,获取了2016-10-17中国青海杂多Mw 5.9级地震的同震形变场,基于弹性半空间位错理论反演确定了杂多地震断层滑动模型,采用边界元法计算得到了区域应变场作用下震中范围内典型断层的平均滑动角,进而结合区域断裂带特征、杂多地震断层滑动模型和边界元计算结果对地震断层滑动进行了分析。结果表明,杂多地震形变沿升轨、降轨视线向的最大沉降量分别为-3.6 cm、-3.8 cm;地震断层滑动未延伸至地表,主要集中在-3.80^-16.17 km深度范围内,最大值约0.27 m,平均滑动角为-36.04°;地震矩为7.70×1017N·m,矩震级为Mw 5.9级;杂多Mw 5.9级地震断层滑动可能与区域应变场作用下北东东(north east east,NEE)向断层以左旋走滑为主兼有正断分量的破裂相关。Objectives:At 15:14 on October 17,2016(Beijing time),an earthquake with a magnitude of Mw 5.9 occurred in Zadoi County,Qinghai Province,which is located in the Qiangtang block in the middle of the Tibetan Plateau.The occurrence of the event provides an opportunity to deepen the understanding of the movement characteristic of regional fault zone.The fault slip model of the Zadoi earthquake is further investigated with geodetic observation to understand the fault rupture property of the event better.The rupture characteristic of typical faults around the epicenter is quantitatively studied using numerical method,which can make up for the inadequacies of qualitative interpretation of seismic fault rupture using feature of earthquake sequence and regional geological structure in the previous studies.Methods:To study this earthquake,coseismic deformation field was obtained using interferometric synthetic aperture radar(InSAR)technique and Sentinel-1 satellite ascending and descending synthetic aperture radar(SAR)data.On the basis of comparative analysis of existing studies related to rupture model of seismic fault,the fault slip model of this event was then inverted with the elastic half-space dislocation theory and non-negative least squares method.The average rakes of typical faults around the epicenter under regional strain field were calculated with boundary element method,and the earthquake fault slip was finally analyzed by combining the characteristic of regional faults,the fault slip model of the Zadoi earthquake and the result calculated by boundary element method.Results:The main results are given as follows:(1)The ascending and descending InSAR coseismic deformation field is continuous and smooth as a whole,and the local surface deformation feature around the epicenter is obvious.The standard deviations for the ascending and descending observations are 4.3 mm and 3.4 mm,respectively.The maximum subsidences along the line of sight of ascending and descending orbits are-3.6 cm and-3.8 cm,respectively.The defo

关 键 词：杂多Mw 5.9级地震 INSAR 反演 地震断层滑动 边界元分析 

分 类 号：P237[天文地球—摄影测量与遥感]