2023年甘肃积石山M_(S)6.2地震地表破裂及震害特征分析  

Surface rupture and damage characteristics of the 2023 M_(S)6.2 Jishishan earthquake,Gansu

作　　者：苏瑞欢 袁道阳 郑文俊 王爱国 李智敏[5] 文亚猛 魏拾其 莫金泉 陈艳文 张梨君 SU RuiHuan;YUAN DaoYang;ZHENG WenJun;WANG AiGuo;LI ZhiMin;WEN YaMeng;WEI ShiQi;MO JinQuan;CHEN YanWen;ZHANG LiJun(School of Earth Sciences,Lanzhou University,Lanzhou 730000,China;Guangdong Provincial Key Laboratory of Geodynamics and Geohazards,School of Earth Sciences and Engineering,Sun Yat-sen University,Guangzhou 510275,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai Guangdong 519082,China;Gansu Earthquake Agency,Lanzhou 730000,China;Qinhai Earthquake Agency,Xining 810001,China)

机构地区：[1]兰州大学地质科学与矿产资源学院,兰州730000 [2]中山大学地球科学与工程学院,广东省地球动力作用与地质灾害重点实验室,广州510275 [3]南方海洋科学与工程广东省实验室(珠海),广东珠海519082 [4]甘肃省地震局,兰州730000 [5]青海省地震局,西宁810001

出　　处：《地球物理学报》2024年第9期3454-3471,共18页Chinese Journal of Geophysics

基　　金：第二次青藏高原综合科学考察研究(2019QZKK0901);国家自然科学基金(42172227);青海省基础研究计划项目"青海玛多7.4级地震发震构造模型及未来地震危险性研究"(2022-ZJ-749)共同资助。

摘　　要：2023年12月18日,在甘肃省积石山县(102.79°E,35.70°N)发生了M_(S)6.2地震,震源深度约10 km,性质以挤压逆冲为主,兼有少量右旋走滑分量.根据现场应急考察结果,本次地震震中位于拉脊山北缘断裂带南东段的积石山东缘断裂上,震区附近该断裂由4条次级断裂组成,包括积石峡断裂、大墩村断裂、赵木川断裂和大河家断裂,构成较复杂的几何图像.沿各次级断裂形成了多处具有两组优势方向的构造地裂缝和雁列状裂缝带,并沿大墩村断裂、赵木川断裂和大河家断裂形成了少量厘米级同震逆冲(位错值2~4 cm)和右旋位错(位错值3 cm)现象.综合前人小震精定位结果认为,积石山东缘断裂的大墩村断裂、赵木川断裂和大河家断裂等三条次级断裂共同构成本次地震的发震构造,实际上这是一次积石山东缘断裂向临夏盆地内部挤压扩展过程中,次级断裂活动的地震事件,而其主断裂(积石峡断裂)全新世有新活动的地质地貌证据,本次地震应力可能未完全释放,其未来发生更大地震的危险性应引起重视.本次地震还引发了不同类型的崩塌、滑坡、边坡滚石、液化—泥流、房屋破坏等一系列地质灾害及建筑物震害,造成了上百人遇难和严重的经济损失.通过对极震区大墩村典型黄土台塬不同部位震害特征的调查分析,发现地震对黄土台塬上部早期建设的老旧房屋及围墙造成了严重垮塌破坏,而在台塬中部的斜坡部位造成了多处规模不等的崩塌、滑坡、地表张性裂缝等边坡失稳现象,在台塬下部谷地地表裂缝及房屋震害较轻.考虑到黄土台塬上部及斜坡的场地放大效应是造成本次地震灾害严重的重要原因之一,后续应考虑黄土台塬区域村镇房屋加固及工程建设针对性抗震设防的必要性.On December 18,2023,an earthquake of M_(S)6.2 occurred in Jishishan County,Gansu Province(102.79°E,35.70°N)with a focal depth of about 10 km.The earthquake was dominated by compressional thrusting with a small component of dextral strike-slip motion.According to the results of on-site emergency investigation,the epicenter of this earthquake was located on the East Jishishan fault(EJSSF),which is part of the southeastern segment of the North Lajishan fault zone(NLJSF).Near the epicenter,the EJSSF is composed of four secondary faults,including Jishixia fault(JSXF),Daduncun fault(DDCF),Zhaomuchuan fault(ZMCF),and Dahejia fault(DHJF),forming a relatively complex geometric pattern.Multiple tectonic fractures with two dominant directions and echelon fracture zones were formed along these secondary faults,and a small amount of centimeter-scale coseismic thrusting(dislocation value 2~4 cm)and right-lateral dislocation(dislocation value 3 cm)phenomena were formed along the DDCF,ZMCF and DHJF.Based on the results of previous small earthquake localization,it is concluded that the three secondary faults include the DDCF,ZMCF and DHJF of the EJSSF constitute the seismogenic structure of this earthquake.In fact,this is an earthquake event caused by the activity of secondary faults during the process of EJSSF expanding towards the interior of the Linxia Basin.Geological and geomorphic evidence indicates that the main fault(JSXF)has been active during the Holocene,the stress of the region may not be completely released by this earthquake,and the risk of larger earthquakes occurring in the future should be given sufficient attention.This earthquake also triggered a series of geological hazards and building damages such as different types of collapses,landslides,rolling rocks on slopes,liquefaction-mudflows and house damages,causing hundreds of casualties and severe economic losses.Through the investigation and analysis of the earthquake damage characteristics in different parts of the typical loess tableland in Dadun Village of

关 键 词：积石山M_(S)6.2地震 积石山东缘断裂 同震破裂 地震灾害 

分 类 号：P541[天文地球—构造地质学]