甘肃积石山Ms 6.2地震深部构造特征和动力学过程  

Deep Structural Characteristics and Dynamic Processes of the Ms 6.2 Jishishan Earthquake and Its Adjacent Areas

作　　者：庞琪沛 吴云龙 徐景田[1] 史绪国 张毅[2] PANG Qipei;WU Yunlong;XU Jingtian;SHI Xuguo;ZHANG Yi(School of Geography and Information Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China;Key Laboratory of Geological Survey and Evaluation of Ministry of Education,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)地理与信息工程学院,湖北武汉430074 [2]中国地质大学(武汉)地质探测与评估教育部重点实验室,湖北武汉430074

出　　处：《武汉大学学报(信息科学版)》2025年第2期356-367,共12页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(42274111,41931074,42374032)。

摘　　要：2023‑12‑18甘肃临夏回族自治州积石山县发生Ms 6.2地震,这是2023年造成中国人员伤亡最严重的地震。强震的孕育和发生受区域应力场及主要活动断裂带的控制,以及深部物性结构和动力学环境的影响。在震源区及周边区域开展深部构造特征和孕震环境研究,对于揭示该地区强震成因及开展防震减灾工作具有重要意义。基于XGM2019e全球重力场模型,利用小波多尺度分析和三维地壳密度结构反演等方法对布格重力异常数据进行了处理和分析,从重力学的角度分析了研究区域深部构造特征和动力学过程。结果表明,震源区及周边布格重力异常整体表现为负异常,变化范围在−170~−530 mGal之间,上、中地壳构造运动活跃,地壳内部出现高、低密度体错综复杂的现象。该区域位于阿拉善块体、鄂尔多斯块体和青藏高原块体之间的一条弧形重力梯度条带上,计算结果佐证了青藏高原物质在板块碰撞的影响下向东运移,在受到阿拉善块体和鄂尔多斯盆地的阻拦后沉积下来。综上,板块运动造成的大规模运动调节与地壳深浅部的相互作用共同促使了该地区地震的多发。Objectives:On December 18,2023,an Ms 6.2 earthquake occurred in Jishishan County,Gansu Province.The breeding and occurrence of strong earthquakes are controlled by the regional stress field and the main active fault zone,as well as the deep physical structure and dynamic environment.It is of great significance to study the deep structure characteristics and seismogenic environment in the focal area and its adjacent areas to reveal the causes of strong earthquakes and to carry out the work of earthquake prevention and disaster reduction.Methods:Based on the XGM2019e global gravity field model,the Bouguer gravity anomaly data are processed and analyzed by using wavelet multi-scale analysis and three-dimensional crustal density structure inversion,and the deep structural characteristics and dynamics processes in the study area are analyzed from the perspective of gravity mechanics.Results:The Bouguer gravity anomaly in the focal area and its adjacent areas is a negative anomaly,and the variation range is between−170–−530 mGal.The tectonic movement in the upper and middle crust of this region is active,and a complex phenomenon of high-density and low-density bodies appears inside the crust.This area is in an arc-shaped gravity gradient belt between the Alxa block,Ordos block and the Tibetan Plateau block.The calculation results show that the Tibetan Plateau material migrated eastward under the influence of plate collision and was deposited after being obstructed by the Alxa block and Ordos Basin.Conclusions:The large-scale motion adjustment caused by plate movement and the interaction between the deep and shallow parts of the crust have contributed to the frequent earthquakes in this region.

关 键 词：积石山地震 布格重力异常 地壳密度结构 深部构造特征 孕震环境 

分 类 号：P315[天文地球—地震学]