2025年1月7日西藏定日M_(S)6.8级地震形变场特征及场地效应分析  

Deformation field characteristics and site effect analysis of the M_(S) 6.8 Dingri earthquake in Xizang on January 7,2025

作　　者：赵伟华[1,2] 许强 吉锋[1,2] 解明礼[1,2] 范宣梅 王运生[1,2] 赵建军[1,2] ZHAO Weihua;XU Qiang;JI Feng;XIE Mingli;FAN Xuanmei;WANG Yunsheng;ZHAO Jianjun(State Key Laboratory of Geohazard Prevention and Geological Environment Protection,Chengdu University of Technology,Chengdu 610059,China;College of Environmental and Civil Engineering,Chengdu University of Technology,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]成都理工大学环境与土木工程学院,成都610059

出　　处：《成都理工大学学报(自然科学版)》2025年第2期173-184,共12页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：地质灾害防治与地质环境保护全国重点实验室自主研究课题(SKLGP2023Z021,SKLGP2024K030);国家社会科学基金重大项目(24&ZD164)。

摘　　要：2025年1月7日9时5分,西藏自治区日喀则市定日县(28.50°N,87.45°E)发生M_(S)6.8级地震,震源深度10 km。本次地震发生在申扎—定结裂谷与藏南拆离系的交汇区域,是近年来该区域发生的最大地震。采用现场调查、雷达遥感分析和光学遥感解译等方法,对西藏定日M_(S)6.8级地震的地质背景、形变场、地表破裂特征以及地震场地效应进行了较为详细的分析,得到以下成果。(1)通过InSAR技术分析和光学遥感解译,揭示了地震造成的强烈地表位移,断层主要表现为北段上盘的垂直向下位移分量和相对左旋位移分量,因此可以推断登么错断裂的运动机制以北段的上盘正断运动为主,兼少量左旋运动。(2)地震引发的地表破裂显著,北段破裂显著而南段相对较弱,破裂带与登么错湖边界形态较为一致,整体表现为拉张陷落特征。(3)场地效应方面,地震导致房屋建筑严重破坏,表现为断裂带破坏效应、上盘效应、延伸方向效应和房屋结构效应,特别是土木结构的房屋受损严重;此外,地震未诱发大规模地质灾害,仅在局部地区发现少量滑坡和崩塌。本研究可为深入理解该地区地震活动规律、提升地震灾害防范能力以及灾后重建提供一定科学依据。At 09:05 PM on January 7,2025,a magnitude 6.8 earthquake struck Dingri County(28.50 degrees north latitude,87.45 degrees east longitude)in Rikaze City,Xizang,with a epicenter depth of 10 km.It was the largest earthquake in this area in recent years.The earthquake occurred in the intersection area of the Shenzha–Dingjie rift valley and southern Tibet detachment system.By means of field investigation,radar remote sensing analysis,and optical remote sensing interpretation,the geological background,deformation field,surface rupture characteristics,and seismic site effects of the M_(S) 6.8 Dingri earthquake in Xizang are analyzed in detail.The following results were obtained:(1)Through InSAR technology analysis and optical remote sensing interpretation,it is revealed that the strong surface displacement caused by the earthquake mainly manifested as a vertical downward component and a relative left-lateral component of the upper wall in the northern section.It is inferred that the motion mechanism of the ascending fault is mainly normal fault movement of the upper wall in the north section,with a small amount of leftlateral movement.(2)Surface ruptures induced by the earthquake are significant,where that in the northern section is significant and that in the southern section is relatively weak.The rupture zone is consistent with the boundary shape of Dengmocuo Lake,and the overall characteristics are characterized by tension collapse.(3)In terms of site effect,the earthquake caused serious damage to buildings,which manifested as fault zone damage,hanging walls,fault extension direction,and house damage;in particular,soil and wooden houses were seriously damaged.In addition,the earthquake did not induce large-scale geological disasters,and only a small number of landslides and collapses were found in local areas.The research in this paper provides a scientific basis for understanding the seismic activity in this area,improving the ability of earthquake disaster prevention and post-disaster reconstruction.

关 键 词：西藏定日县 6.8级地震 InSAR形变场 地表破裂 场地效应 

分 类 号：P642.2[天文地球—工程地质学]