2025年1月7日西藏定日M_(S)6.8级地震InSAR同震形变探测与断层滑动分布反演  

InSAR coseismic deformation detection and fault slip distribution inversion of the M_(S)6.8 earthquake in Dingri,Tibet on January 7,2025

作　　者：李雨森 李为乐[1,2] 许强 陆会燕[1] 何国庆 范禄震 秦佳松 LI Yusen;LI Weile;XU Qiang;LU Huiyan;HE Guoqing;FAN Luzhen;QIN Jiasong(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Laboratory of Landslide Risk Early-Warning and Control,Chengdu 610059,China)

机构地区：[1]地质灾害防治与地质环境保护全国重点实验室(成都理工大学),成都610059 [2]滑坡灾害风险预警与防控应急管理部重点实验室,成都610059

出　　处：《成都理工大学学报(自然科学版)》2025年第2期199-211,共13页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家社会科学基金重大项目(24&ZD164)。

摘　　要：2025年1月7日西藏自治区日喀则市定日县发生M_(S)6.8级地震,震中位于青藏高原与印度板块交界处的申扎-定结断裂带附近,是近年来该区域发生的最大地震。为深入了解此次地震的同震形变特征,基于合成孔径雷达差分干涉测量技术(Differential InSAR,D-InSAR),利用陆地探测一号卫星升轨、Sentinel-1降轨数据获取了此次地震的同震形变场,对发震断层进行滑动分布反演,计算了区内不同深度的同震库伦应力变化。结果表明,此次地震造成的地表变形区可达160 km×100 km,变形集中发生在登么错断裂西侧,沿卫星视线向方向升轨最大形变量为−1.538 m,降轨方向最大形变量为0.68 m;反演结果显示,破裂断层以正断性质为主,兼有少量走滑性质,滑动主要分布在地下0~14 km范围内,最大滑动量约4.73 m。通过反演结果及地质资料综合判断,本次发震断层为登么错断裂;不同深度的同震库伦应力变化表明藏南滑脱拆离系断裂带、申扎-定结断裂带,扎达-拉孜-邛多江断裂带中部区域均处于应力加载区,未来需重点关注。An M_(S)6.8 earthquake occurred in Dingri County,Shigatse City,Tibet Autonomous Region on 7 January 2025,which is the largest earthquake to have occurred in recent years.The macro-earthquake epicenter was located near the Shenzha-Dingjie fault zone at the junction of the Tibetan Plateau and the Indian Plate.To understand the characteristics of this earthquake,we determined the coseismic deformation field of this earthquake based on InSAR technology,using the data from Lutan-1(ascending orbit)and Sentinel-1(descending orbit).These data were used to invert the sliding distribution of the seismic fault,and to calculate the coseismic coulombic stress changes at different depths in the region.The results show that the surface deformation caused by this earthquake is up to 160×100 km,and the deformation is concentrated on the west side of the Dengmecuo fault,with a maximum deformation of-1.538 m along the satellite’s line of sight,and a maximum vertical deformation of 0.68 m.The inversion results show that the ruptured faults are mainly positively faulted,with a small amount of strike-slip,and the slips are mainly located in the range of 0~14 km below ground.The maximum amount of sliding is about 4.73 m.Based on a comprehensive evaluation of the inversion results and geological data,we find that the Dengmeco fault generated this earthquake.The columb stress change at different depths shows that the south Tibetan sliding disassemblage system fracture zone,the Shenzha-Dingjie fracture zone,and the central part of the Zhada-Lazi-Qiongduojiang fracture zone are all in the stress-loading zone,which need to be better understood and studied.

关 键 词：定日地震 合成孔径雷达差分干涉测量 同震形变 断层滑动分布反演 

分 类 号：P237[天文地球—摄影测量与遥感]