摘要
为研究2019年四川长宁地震前后地壳内部物质的运移过程,文中利用流动重力和GNSS资料对地震前后的重力变化特征、地壳垂直形变及其关系进行了深入分析。地震震中处于重力变化正、负异常的梯度带上,并在地震前后呈现明显反向。小波多尺度分解表明,浅部的离散性局部变化特征明显,深部的趋势变化特征显著。震中周边4个站点的重力变化与地壳垂直形变的关系与近似规律不一致。长宁震区长期的动力是青藏高原的物质在深部向四川盆地南边界运移的结果。在震中及周边区域的地表浅层可能存在一些空洞或气囊等空间,在地震前后出现气体、液体或高密度物质流失和填充的现象。结合前人对长宁地震发震机制的研究成果分析认为,该区域的采盐、采气及废水回注等因素可能是触发四川长宁地震的原因之一。
The MS6.0 Changning earthquake in Sichuan Province caused heavy casualties and property losses.Many scholars have carried out a lot of research on the tectonic background and seismogenic mechanism of the earthquake.However,whether the triggering mechanism of the earthquake is related to fluid injection remains controversial,and further comprehensive analysis should be conducted based on multidisciplinary observation data.The preparation and occurrence of large earthquakes are often closely related to crustal deformation and mass density changes.The comprehensive study of these two methods is conducive to capturing the real crustal dynamics information.To study the process of material migration in the earth's crust before and after the earthquake and its triggering mechanism,the characteristics of gravity changes before and after the earthquake,the crustal vertical deformation data and their relationship were analyzed by using the gravity and GNSS data in Sichuan.The characteristics of regional gravity change before and after the earthquake show that the epicenter of the Changning earthquake is located in the gradient zone of positive and negative gravity change anomalies and presents obvious reverse before and after the earthquake.According to the summary of previous earthquake cases,this region may have entered the short-and medium-term stages of earthquake preparation.The wavelet multi-scale decomposition method is used to process the regional gravity change characteristics of two periods before and after the earthquake,and the gravity change characteristics of different depths and scales are obtained.The results show that in the shallow part of the seismic region,the local variation characteristics of the dispersion are obvious,mainly distributed in the boundary of the active fault zone and block.The trend change characteristics are significant in the deep part,and the gravity gradient zone associated with the earthquake is found.In theory,there is an approximate ratio relationship between surface gravity chan
作者
王嘉沛
谈洪波
李忠亚
刘少明
张毅
郝洪涛
胡敏章
申重阳
WANG Jia-pei;TAN Hong-bo;LI Zhong-ya;LIU Shao-ming;ZHANG Yi;HAO Hong-tao;HU Min-zhang;SHEN Chong-yang(Key Laboratory of Earthquake Geodesy,Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;Gravitation and Earth Tide,National Observation and Research Station,Wuhan 430071,China;Key Laboratary of Geological Survey and Evaluation of Ministry of Education,China University of Geosciences(Wuhan),Wuhan 430074,China)
出处
《地震地质》
EI
CSCD
北大核心
2023年第4期952-969,共18页
Seismology and Geology
基金
国家自然科学基金(42204089)
国家重点研发计划项目(2018YFE0206100,2017YFC1500204)
武汉引力与固体潮国家野外科学观测研究站开放研究基金(WHYWZ202108)共同资助
关键词
重力变化
地壳垂直形变
比值关系
小波多尺度分解
长宁地震
Gravity change
crustal vertical deformation
ratio relationship
wavelet multi-scale decomposition
Changning earthquake
