联合InSAR和高频GNSS位移波形反演2022年青海门源M 6.9地震同震破裂过程  

Joint inversion of InSAR and high-rate GNSS displacement waveforms for the rupture process of the 2022 Qinghai Menyuan M 6.9 earthquake

作　　者：吕明哲 陈克杰 柴海山 耿江辉[2] 张生鹏 房立华[5] Lü MingZhe;CHEN KeJie;CHAI HaiShan;GENG JiangHui;ZHANG ShengPeng;FANG LiHua(Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen 518055,China;GNSS Research Center,Wuhan University,Wuhan 430079,China;School of Geographic Science,Qinghai Normal University,Xining 810016,China;Qinghai Basic Surveying and Mapping Institute,Xining 810101,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]南方科技大学地球与空间科学系,深圳518055 [2]武汉大学卫星导航定位技术研究中心,武汉430079 [3]青海师范大学地理科学学院,西宁810016 [4]青海省基础测绘院,西宁810101 [5]中国地震局地球物理研究所,北京100081

出　　处：《地球物理学报》2022年第12期4725-4738,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42074024);中国科协青年人才托举工程联合资助.

摘　　要：使用差分干涉测量和像素偏移追踪从Sentinel-1 SAR卫星影像中提取了2022年青海门源M 6.9地震视线向位移及近断层距离向偏移,通过单历元精密单点定位获取了16个GNSS测站高频位移波形.基于上述观测资料的同震破裂过程联合反演结果表明,该地震使两个走向分别为82°和112°的断层面发生破裂,为双侧不对称破裂事件,总破裂长度~26 km,滑动集中分布在0~5 km深度,最大滑动量为~4 m,总地震矩释放量为8.65×10^(18) Nm(对应矩震级为M_(W)6.56),在~10 s内全部释放.同震库仑应力变化结果表明,主震使两条发震断层在10 km深度处库仑应力增加,促进了该区域后续余震发生.滑动分布模型显示门源地震浅层滑动亏损较小,结合已有2014至2021年时序InSAR结果,推测在更长震间期内,与两条发震断层相近的冷龙岭断裂和托莱山断裂不存在明显的浅层蠕滑.Using differential interferometric synthetic aperture radar(InSAR)and pixel offset tracking,we obtained both the coseismic displacements along line-of-sight and near-field range offsets of the 2022 Qinghai Menyuan M 6.9 earthquake from Sentinel-1 SAR images,and also got high-rate displacement waveforms at 16 Global Navigation Satellite System stations through epoch-wise precise point positioning solutions.Based on these measurements,we then jointly inverted the rupture process of the 2022 Menyuan M 6.9 earthquake.Our results show that this earthquake was a bilateral asymmetric event,which ruptured two faults at strikes of 82°and 112°with a total length of~26 km.Most of the slip occurred between 0 and 5 km,and the peak slip was~4 m.A total seismic moment of 8.65×10^(18) Nm(equivalent to M_(W)6.56)was released within~10 s.Coulomb failure stress change analysis indicates that stress levels of two neighbouring seismogenic faults at 10 km were increased,which was responsible for the subsequent aftershocks in this region.Our slip model implies insignificant shallow slip deficits,considering InSAR time series from 2014 to 2021,so we speculated that there should be negligible shallow creeping along Lenglongling and Tuolaishan segments during the long-term interseismic period.

关 键 词：青海门源M 6.9地震 INSAR 高频GNSS 联合反演 

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]