2024年1月23日新疆乌什M_(S)7.1地震地质灾害和地表破裂  

GEOLOGICAL DISASTERS AND SURFACE RUPTURES OF JANUARY 23,2024 M_(S)7.1 WUSHI EARTHQUAKE,XINJIANG,CHINA

作　　者：张博譞 钱黎 李涛[1,2,3] 陈杰 许建红[4] 姚远 房立华[6] 谢超 陈建波[5] 刘冠伸[1] 胡宗凯 杨文心[1,2,3] 张军龙 庞炜 ZHANG Bo-xuan;QIAN Li;LI Tao;CHEN Jie;XU Jian-hong;YAO Yuan;FANG Li-hua;XIE Chao;CHEN Jian-bo;LIU Guan-shen;HU Zong-kai;YANG Wen-xin;ZHANG Jun-long;PANG Wei(Institute of Geology,China Earthquake Administration,State Key Laboratory of Earthquake Dynamics,Beijing 100029,China;Xinjiang Pamir Intracontinental Subduction National Observation and Research Station,Beijing 100029,China;Urumqi Institution of Central Aisa earthquake,China,Earthquake Administration,Urumqi 830011,China;The Second Monitoring and Application Center,China Earthquake Administration,Xi′an 710054,China;Earthquake Agency of the Xinjiang Uygur Autonomous Region,Xinjiang,Urumqi 830011,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Institute of Earthquake Forecasting,China Earthquake Administration,Key Laboratory of Seismic Prediction,Beijing 100036,China)

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [2]新疆帕米尔陆内俯冲国家野外科学观测研究站,北京100029 [3]中国地震局乌鲁木齐中亚地震研究所,乌鲁木齐830011 [4]中国地震局第二监测中心,西安710054 [5]新疆维吾尔自治区地震局,乌鲁木齐830011 [6]中国地震局地球物理研究所,北京100081 [7]中国地震局地震预测研究所,地震预测重点实验室,北京100036

出　　处：《地震地质》2024年第1期220-234,共15页Seismology and Geology

基　　金：国家重点研发计划项目(2022YFC3003700,2023YFC3007401);国家自然科学基金(41772221);中国地震局地质研究所乌什地震应急科考项目共同资助。

摘　　要：2024年1月23日新疆乌什M_(S)7.1地震是自1992年吉尔吉斯斯坦Suusamyr M_(S)7.3地震以来发生在天山地震带内的最大地震。主余震初步精定位和第一时间野外调查结果表明,乌什MS7.1地震的余震带总体走向NE,长约62km,主要分布在盆山交接部位。地震产生了边坡失稳、岩崩、滚石、地裂隙等次生地质灾害,主要集中在沿构造走向微观震中两侧30km范围内。由微观震中向N约7km、向S约13km以外,地质灾害迅速减轻,且山前断层陡坎(F_(5))未见任何新鲜的活动迹象。结合中国地震局地质研究所产出的InSAR同震形变场初步结果,判定此次主震的发震断层为一条倾向NW、未错出地表的逆冲断层。在GCMT震中所在的恰勒玛提河,沿西域砾岩背斜南翼发现了总体走向N60°E、长约2km、最大垂直位错约1m的地震地表破裂带。该地表破裂在较老地貌面上基本沿先存断层陡坎发育,总体受一条倾向SE、与主震发震断层倾向相反的逆断裂控制。地表破裂带长2km,规模远小于乌什M_(S)7.1地震余震带,其是由M_(S)7.1主震所致还是因M_(S)5.7余震造成的,以及产生地表破裂的SE倾逆断层与NW倾主震发震断裂之间是何种关系,还需进一步研究。The M_(S)7.1 earthquake in Wushi,Xinjiang on January 23,2024,represents the largest earthquake in the Tianshan seismic belt since the 1992 Suusamyr M_(S)7.3 earthquake in Kyrgyzstan.Preliminary precise aftershock localization and initial field investigations indicate an NE-trending aftershock zone with a length of 62km that is concentrated at the mountain-basin transition area.This event produced geological hazards,including slope instability,rockfalls,rolling stones,and ground fissures,primarily within a 30-kilometer radius around the epicenter.The epicenter,located approximately 7 kilometers north of the precise positioning in this study,witnessed a rapid decrease in geological hazards such as collapses,with no discernible fresh activity observed on the steep fault scarp along the mountainfront.Consequently,it is inferred that the causative fault for this main shock may be an NW-dipping reverse fault,with potential rupture not reaching the surface.Moreover,a surface rupture zone with a general trend of N60°￣E,extending approximately 2 kilometers,and displaying a maximum vertical offset of 1m,was identified on the western side of the micro-epicenter at the Qialemati River.This rupture zone predominantly follows the pre-existing fault scarp on higher geomorphic surfaces,indicating that it is not new.Its characteristics are mainly controlled by a southeast-dipping reverse fault,opposite in dip to the causative fault of the main shock.The scale of this 2-kilometer-long surface rupture zone is notably smaller than the aftershock zone of the Wushi M_(S)7.1 earthquake.Further investigation is warranted to elucidate whether or not the M_(S)5.7 aftershock and the relationship between the SE-dipping reverse fault responsible for the surface rupture and the NW-dipping causative fault of the main shock produced it.

关 键 词：天山 乌什盆地 逆断型强震 地表破裂 次生地质灾害 

分 类 号：P315.2[天文地球—地震学]