利用空间观测技术研究青海玛多7.4级地震孕育发生变形时空特征  

Using space observation techniques to study temporal and spatial characteristics of seismogenic process,occurrence and deformation of the Qinghai Madoi M_(w) 7.4 earthquake

作　　者：姜卫平[1] 许才军[2] 李志伟[3] 武艳强[4] 谭凯[5] 耿江辉[1] 屈春燕[6] 郑刚[1] 温扬茂[2] 贺克锋 周晓慧[2] 刘计洪 陈长云[4] 冯光财[3] 省天琛 JIANG WeiPing;XU CaiJun;LI ZhiWei;WU YanQiang;TAN Kai;GENG JiangHui;QU ChunYan;ZHENG Gang;WEN YangMao;HE KeFeng;ZHOU XiaoHui;LIU JiHong;CHEN ChangYun;FENG GuangCai;XING TianChen(GNSS Research Center,Wuhan University,Wuhan 430079,China;School of Geodesy and Geomatics,Wuhan University,Wuhan 430079,China;School of Geosciences and Info-physics,Central South University,Changsha 410012,China;The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China;Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;Institute of Geology,China Earthquake Administration,Beijing 100029,China;Qinghai Basic Surveying and Mapping Institute,Xining 810101,China)

机构地区：[1]武汉大学卫星导航定位技术研究中心,武汉430079 [2]武汉大学测绘学院,武汉430079 [3]中南大学地球科学与信息物理学院,长沙410012 [4]中国地震局第一监测中心,天津300180 [5]中国地震局地震研究所,武汉430071 [6]中国地震局地质研究所,北京100029 [7]青海省基础测绘院,西宁810101

出　　处：《地球物理学报》2022年第2期495-508,共14页Chinese Journal of Geophysics

基　　金：国家重点研发计划项目(2018YFC1503600);国家自然科学基金项目(42025401)资助。

摘　　要：为揭示2021年青海玛多7.4级地震震前变形与同震破裂特征,本文系统收集与处理了青海省CORS站和中国地壳运动观测网络等GNSS资料、以及Sentinel-1和ALOS-2卫星SAR数据,通过多源数据综合处理获取了玛多地震形变场动态结果.震前GNSS形变场结果显示,玛多震源区处于其北侧剪切形变高值区边缘,震前存在左旋剪切应变积累.同震三维形变场结果表明,昆仑山口—江错断裂发生了显著的左旋破裂,同震形变主要发生在昆仑山口—江错断裂两侧100 km范围内,最大水平形变量达到2.4 m,垂直形变主要发生在近断层区域且在断层两侧呈现正负交替现象,表明地震破裂的断层倾角在空间上存在多样性特征.三维形变场联合反演结果揭示玛多地震的滑动破裂直达地表,主要分布在15 km深度以上,最大滑动量约为4 m,矩震级为M_(w)7.4,并且破裂在断层走向上呈现明显的分段特征,形成了5个不连续的显著滑动区.In order to reveal the characteristics of pre-seismic deformation and co-seismic rupture of the 2021 Qinghai Madoi M_(w)7.4 earthquake,we systematically collect the GNSS data from Qinghai CORS and Crustal Movement Observation Network of China and the SAR data from Sentinel-1 and ALOS-2 satellites,and obtain the dynamic deformation field of the Madoi earthquake by the integrated processing of multi-source data.The pre-seismic GNSS deformation field shows that the Madoi focal area is located at the edge of the high-value region of shear deformation in the north of the earthquake,and sinistral shear strain was accumulated there before the earthquake.The 3-D co-seismic deformation field shows that the KunlunshanPass-Jiangcuo fault has a significant sinistral rupture,and the co-seismic deformation mainly occurs within 100 km from the fault with a maximum horizontal component of 2.4 m.The vertical co-seismic deformation mainly occurs in the vicinity of the fault,and shows alternately positive and negative variation from one side of the fault to the other,which reveals the spatial diversity of dip angles of the ruptured fault.The result of the joint inversion of GNSS and InSAR shows that the rupture of the Madoi earthquake reaches the surface,which is mainly distributed above 15 km depth,with the maximum slip value at about 4 m,and the moment magnitude is about 7.4.The rupture along the fault strike shows an obvious segmental characteristic,and five regions with significant slip values are distributed discontinuously.

关 键 词：玛多地震 GNSS观测 多源InSAR 断层滑动分布反演 

分 类 号：P228[天文地球—大地测量学与测量工程] P315[天文地球—测绘科学与技术]