2025年M_(w)7.1西藏定日地震地表破裂与同震位移分布特征  

Co-seismic surface rupture of the 2025 M_(w)7.1 Tingri earthquake and potential seismic risk in southern Tibetan Plateau

作　　者：刘富财 潘家伟[1,2,3] 李海兵 杨少华[1,2] 吴坤罡 苏强[1] 张斯琪 Marie-Luce CHEVALIER 卢海建 LIU Fucai;PAN Jiawei;LI Haibing;YANG Shaohua;WU Kungang;SU Qiang;ZHANG Siqi;Marie-Luce CHEVALIER;LU Haijian(Key Laboratory of Continental Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Jiangsu Donghai Continental Deep Hole Crustal Activity National Observation and Research Station,Lianyungang,Jiangsu 222300,China;State Key Laboratory of Deep Earth and Mineral Exploration,Beijing 100094,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China)

机构地区：[1]中国地质科学院地质研究所,自然资源部大陆动力学重点实验室,北京100037 [2]江苏东海大陆深孔地壳活动国家野外科学观测研究站,江苏连云港222300 [3]深地探测与资源勘查全国重点实验室,北京100094 [4]中国地质科学院地质力学研究所,自然资源部活动构造与地质安全重点实验室,北京100081

出　　处：《地质学报》2025年第3期685-703,共19页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42372274,42325207);科技基础资源调查专项(编号2021FY100101);中国地质调查局项目(编号DD20240041);中国地质科学院地质力学所基本科研业务费项目(编号DZLXJK202413)联合资助的成果。

摘　　要：2025年1月7日9时5分,西藏日喀则市定日县发生了M_(w)7.1级强烈地震,震中位于措果乡(28.50°N,87.45°E),震源深度10 km。震后的野外现场考察表明,这次地震是一次伴随左行走滑分量的正断型地震事件,发震构造为青藏高原南部申扎-定结裂谷南段的丁木错断裂。地震沿丁木错地堑东缘和拉轨岗日山西侧谷地东缘形成了长约35 km的不连续同震地表破裂带。破裂带沿先存断层陡坎发育,整体近SN走向,以新鲜、西倾的正断层陡坎和张裂隙为主,并在部分位置具有显著的右阶雁列组合特征。根据破裂发育规模和连续性特征,自北向南将同震地表破类带分为羊母丁错姆、尼辖错北东、古荣村东和丁木错段。其中连续性较好的尼辖错北东段和古荣村东段的长度分别为~6 km和~3 km,测量获得的最大同震垂直位移量分别为2.7±0.6 m和~0.9 m,最大走滑位移量分别为~1.1 m和~0.4 m。灾区不同乡村的震害程度与发震断层上盘效应及其与破裂带的距离密切相关。此外,定日地震造成的区域应力变化可能触发了发震断层南东侧郭加断裂和日玛那穹隆的活动,因此郭加断裂、定结断裂未来强震风险增加,需重点关注。At 09:05 Am on January 7,2025,a M_(w)7.1 earthquake occurred in southern Tibetan Plateau,Dingri(Tingri)County,Rikaze(Xigaze)City,Xizang Autonomous Region,China.The epicenter was located at Cuoguo Town(28.50°N,87.45°E),at a depth of 10 km.Field investigation after the earthquake shows that the 2025 Tingri event is a normal-faulting event with left-lateral strike-slip component.The Seismogenic fault is the Dingmu Co-Lagoi fault in the southern segment of the Xainza-Dinggye rift in southern Tibetan Plateau.This event produced~35 km of discontinuous co-seismic surface ruptures along the eastern boundary of the Dingmu Co graben and the west border of the Lagoi Kangri Mountains.The generally NS-trending rupture zone developed along pre-existing fault scarps,and it is dominated by fresh,west-dipping normal fault scarps and tensional cracks.Locally,right-stepping,en-echelon scarps and cracks reveal horizontal strike-slip motion along the rupture.According to the size and continuity of ruptures,the co-seismic surface rupture zone can be divided into four segments from north to south:the Yangmudingcuomu,Nixia Co,Gurong,and Dingmu Co segment.Among them,the continous Nixia Co and Gurong segments are~6 and~3 km-long,respectively.The maximum co-seismic vertical and horizontal(left-lateral strike-slip)displacements measured along the rupture zone are 2.7±0.6 m and~1.1 m,respectively,both located along the Nixia Co segment,while those along the Gurong segment are~0.9 m and~0.4 m,respectively.The damage degree at different places is closely related to the hanging wall effects of the seismogenic fault and its distance from the surface ruptures.In addition,we infer that the regional stress changes caused by the Tingri earthquake may have triggered the activity along the Guojia fault and Ama Drime massif to the southeast.Therefore,the risk of strong earthquakes along Guojia and Dinggye faults may have increased,hence one should pay more attention to those regions.

关 键 词：M_(W)7.1定日地震 同震地表破裂 同震位移 丁木错断裂 申扎-定结裂谷 

分 类 号：P31[天文地球—固体地球物理学]