三峡地区流动重力网地震监测能力研究  

Monitoring Ability Analysis of Three Gorges Gravity Network

作　　者：童广勤 张弛 郝洪涛[3,4] 刘少明 张新林[3,4] 吕品姬 胡敏章[3,4] Tong Guangqin;Zhang Chi;Hao Hongtao;Liu Shaoming;Zhang Xinlin;Lu Pinji;Hu Minzhang(River Basin Hub Operation Management Center,China Three Gorges Corporation,Yichang 443133,Hubei,China;Hubei Key Laboratory of Operation Safety of High Dam and Large Reservoir,Yichang 443133,Hubei,China;Key laboratory of Earthquake Geodesy,Institute of Seismology,CEA,Wuhan 430071,China;Hubei Earthquake Agency,Wuhan,430071,China)

机构地区：[1]中国长江三峡集团有限公司流域枢纽运行管理中心,湖北宜昌443133 [2]高坝大库运行安全湖北省重点实验室,湖北宜昌443133 [3]中国地震局地震研究所,地震大地测量重点实验室,武汉430071 [4]湖北省地震局,武汉430071

出　　处：《中国地震》2024年第3期563-572,共10页Earthquake Research in China

基　　金：长江三峡工程地震监测总站及地壳形变监测网络升级项目(0404552);2022-2024年长江三峡库区地震监测系统运行维护及地震应急工作项目(1299235);中国地震局地震研究所所长基金资助项目(202326342)共同资助。

摘　　要：重力观测是三峡水库地区地震监测的重要组成部分。本文系统分析了三峡重力网的空间覆盖范围、空间分辨力以及重力变化观测精度,结合现有重力变化异常空间范围和量级与地震震级之间经验指标,对三峡重力网的地震监测能力进行了评估。结果表明,三峡重力网在空间分辨力和观测精度方面均达到了4级以上地震的监测要求,空间覆盖范围介于5级地震重力变化异常场范围经验指标的上、下限之间,因此重力网对于4~5级地震具有较好的监测能力,但对于监测5级以上地震存在无法获取重力变化异常完整形态的可能。此外,三峡水库水位变化引起的重力效应对重力观测具有明显的影响,在计算水位变化重力效应时,应采用与重力观测数据相同时刻的水位数据。Gravity observations constitute a pivotal element within the seismic monitoring framework of the Three Gorges Reservoir region.This paper undertakes a comprehensive analysis of the spatial coverage,resolution,and measurement precision of the Three Gorges gravity network.Utilizing empirical benchmarks for spatial extent and the magnitude of gravitational anomalies in relation to seismic magnitudes,the seismic monitoring capacity of the network is rigorously assessed.The results show that the spatial resolution and observational precision of Three Gorges gravity network are adequate for the detection of earthquakes magnitude 4 and higher.Nonetheless,the spatial coverage extends only partially within the empirically defined parameters for the gravitational anomaly field range associated with magnitude 5 earthquakes.Consequently,while the network demonstrates robust monitoring capabilities for earthquakes ranging from magnitude 4 to 5,its ability to fully delineate the gravitational anomaly patterns triggered by larger seismic events remains uncertain.Furthermore,we find that gravitational variations induced by fluctuations in the water level of the Three Gorges Reservoir exert a considerable influence on gravity measurements.It is imperative to account for these effects by integrating contemporaneous water level data into the gravity observation calculations.

关 键 词：三峡重力网 空间分辨力 重力变化 监测能力 

分 类 号：P315[天文地球—地震学]