2025年1月7日西藏定日6.8级地震发震构造与同震地表破裂特征  

SEISMOGENIC FAULT AND COSEISMIC SURFACE DEFORMATION OF THE DINGRI M_(S)6.8 EARTHQUAKE IN XIZANG,CHINA

作　　者：石峰[1,3] 梁明剑 罗全星[1,3] 乔俊香 张达 王鑫 易文星 张佳伟 张迎峰 张会平[1,5] 李涛 李安[1,3] SHI Feng;LIANG Ming-jian;LUO Quan-xing;QIAO Jun-xiang;ZHANG Da;WANG Xin;YI Wen-xing;ZHANG Jia-wei;ZHANG Ying-feng;ZHANG Hui-ping;LI Tao;LI An(State Key Laboratory of Earthquake Dynamics and Forecasting,Institute of Geology,China Earthquake Administration,Beijing 100029,China;Sichuan Earthquake Administration,Chengdu 610041,China;Shanxi Taiyuan Continental Rift Dynamics Nation Observation and Research Station,Beijing 100029,China;Xingjiang Pamir Intracontinental Subduction National Observation and Research Station,Beijing 100029,China;Lhasa National Geophysical Observation and Research Station,Beijing 100029,China)

机构地区：[1]中国地震局地质研究所,地震动力学与强震预测全国重点实验室,北京100029 [2]四川省地震局,成都610041 [3]山西太原大陆裂谷动力学国家野外科学观测研究站,北京100029 [4]新疆帕米尔陆内俯冲国家野外科学观测研究站,北京100029 [5]西藏拉萨地球物理国家野外科学观测研究站,北京100029

出　　处：《地震地质》2025年第1期1-15,共15页Seismology and Geology

基　　金：中国地震局地质研究所基本科研业务专项(IGCEA2502);地震动力学国家重点实验室自主课题(LED2021A02)共同资助。

摘　　要：2025年1月7日9时5分,西藏自治区日喀则市定日县发生6.8级地震。中国地震台网中心测定震中位于(28.50°N,87.45°E)。通过野外地质调查、震源机制解、余震分布等结果,确定此次地震为正断型地震,发震构造为申扎-定结裂谷断裂系南段的登么错断裂。登么错断裂走向近SN,倾向W,长约60km。此次地震产生的同震地表破裂主要位于登么错盆地以北的山区,产生了长约25km的不连续同震地表破裂带。地表破裂带具有明显的分段特征,根据空间延续性,自南向北可分为3段,依次为古荣—强嘎段、尼辖错段和羊姆丁错段,最大垂直位错量为2.5~3.0m,同时在登么错湖东岸产生了长约10km的地裂缝密集形变带。At 09:05 am on January 7,2025,a M_(S)6.8 earthquake occurred in the Dingri,Xizang,China.The earthquake caused serious casualties and property losses.Research on the seismogenic structure and characteristics of earthquake surface rupture in this earthquake is beneficial to understanding the rupture behavior and dynamic mechanism of normal-fault earthquakes.Meanwhile,it provides a basis for predicting the future strong earthquake trend of the southern Xizang rift fault system.Its epicenter is located at 87.45°-E,28.50°-N,13km depth,the China Earthquake Networks Center measures.In order to constrain the seismogenic fault and characterize the co-seismic surface ruptures of this earthquake,field investigations were conducted immediately after the earthquake,combined with analyses of the focal parameters,aftershock distribution,and InSAR inversion of this earthquake.This preliminary study finds that the seismogenic fault of the Dingri M_(S)6.8 earthquake is the Dengmocuo fault,which is an active~-60km long,NS-NE-striking and normal fault.The total length of the co-seismic surface ruptures is approximately 25km,located on the north segment of the Dengmocuo fault.Meanwhile,a dense deformation zone of ground fracture with a length of~10km is generated on the east side of Dengmocuo Lake along the contour line of the lake shore.The earthquake also induced a large number of liquefaction structures and tensional fractures in valleys and basins.Based on along-strike discontinuity due to the development of step-overs,the coseismic surface rupture zone can be subdivided into three segments:the Gurong-Qiangga,Nixiacuo,and Yangmu-dingcuo segments.The surface ruptures are relatively continuous and prominent along the Nixiacuo segments.Comparatively,co-seismic surface ruptures of Gurong-Qiangga and Yangmu-dingcuo seg-ments are discontinuous.The maximum of coseismic vertical displacement is roughly determined to be 2.5-3.0m based on the scarps.The width of the surface rupture zone of the Dingri earthquake can reach up to 450m in so

关 键 词：定日M_(S)6.8地震 同震地表破裂 发震构造 申扎-定结裂谷断裂系 登么错断裂 

分 类 号：P315.2[天文地球—地震学]