摘要
扫描三峡井网对2013~2022年全球7级以上地震的同震响应,评价三峡井网各井的映震能力,分析影响映震能力的因素,探讨产生台阶型同震响应的条件,并以2008年汶川8.0级地震和2021年玛多7.4级地震为例,利用井水位同震响应对三峡库区的应力调整进行反演。结果显示,地震能量密度与同震响应幅度呈正相关关系;能够引起各井水位产生同震响应的地震能量密度阈值有数量级的差异,反映的是各井的映震能力不同;三峡井网各井映震能力与导水系数正相关,与体积压缩模量、断层距负相关;当地震能量密度大于10^(-3)J/m^(3),且区域构造应力积累较强时,三峡井网井水位同震响应以台阶型为主;通过反演汶川8.0级地震和玛多7.4级地震后三峡井网的应力变化情况,发现应力调整受区域断层控制明显。
We scan the coseismic response of Three Gorges well network to the global earthquakes of magnitude 7 and above during 2013 to 2022,evaluate the reflecting ability of each well in Three Gorges well network,analyze the influencing factors of the reflecting ability,and discuss the conditions for generating step type coseismic response.We take the 2008 Wenchuan 8.0 and the 2021 Maduo 7.4 earthquakes as examples,and use the coseismic response of well water level to inverse the stress adjustment in Three Gorges reservoir area.The results show that there is a positive correlation between seismic energy density and coseismic response amplitude;the threshold values of seismic energy density that can cause the water level of each well to produce coseismic response have an order of magnitude difference,which reflects the different earthquake reflecting capacities of each well;the seismic reflection capacity of the wells in Three Gorges well network are positively correlated with the hydraulic conductivity,and negatively correlated with the bulk compression modulus and the distance from the well to the fault;when the seismic energy density is greater than 10^(-3)J/m^(3)and the regional tectonic stress accumulation is strong,the coseismic response of the well water level in Three Gorges well pattern is mainly stepped.Through inversion of the stress changes in Three Gorges well network after the Wenchuan 8.0 and Maduo 7.4 earthquakes,we find that the stress adjustment is obviously controlled by regional faults.
作者
涂先新
吕品姬
安一凡
曾智辉
TU Xianxin;LÜPinji;AN Yifan;ZENG Zhihui(Key Laboratory of Earthquake Geodesy,CEA,40 Hongshance Road,Wuhan 430071,China)
出处
《大地测量与地球动力学》
CSCD
北大核心
2023年第8期875-880,共6页
Journal of Geodesy and Geodynamics
基金
中国地震局“三结合”课题(3JH-202201025)
长江三峡地震监测项目(2022-0404552,2021-1299235)。
关键词
三峡井网
水位
同震响应
远场强震
应力
Three Gorges well network
water level
coseismic response
far field strong earthquakes
stress
