利用重力卫星研究青海玛多及云南漾濞地震周边2002—2021年重力变化  

STUDY ON GRAVITY VARIATION OF THE EPICENTER AND SURROUNDING AREAS OF MADUO AND YANGBI EARTHQUAKES DURING 2002-2021 BY GRAVITY SATELLITE

作　　者：邹正波[1,2,3,4] 张毅 谈洪波[1] 崔立鲁[5] 尹鹏 吴桂桔 ZOU Zheng-bo;ZHANG Yi;TAN Hong-bo;CUI Li-lu;YIN Peng;WU Gui-ju(Institute of Seismology,CEA,Wuhan 430071,China;Institute of Disaster Prevention,Sanhe,Hebei 065201,China;Gravitation and Earth Tide National Observation and Research Station,Wuhan 430071,China;Hubei Earthquake Agency,Wuhan 430071,China;School of Architecture and Civil Engineering,Chengdu University,Chengdu 610106,China)

机构地区：[1]中国地震局地震研究所,武汉430071 [2]防灾科技学院,三河065201 [3]引力与固体潮国家野外观测研究站,武汉430071 [4]湖北省地震局,武汉430071 [5]成都大学,建筑与土木工程学院,成都610106

出　　处：《地震地质》2021年第4期999-1012,共14页Seismology and Geology

基　　金：国家自然科学基金(41931074,42074172);国家重点研发计划项目(2018YFC1503503);中国地震局地震科技星火计划项目(XH21021)共同资助。

摘　　要：文中基于2002—2021年卫星重力观测数据及全球水文模型,计算了青海玛多及云南漾濞地震震中区及周边(18°~45°~N,83°~115°~E)范围的重力变化趋势、累积重力变化、差分重力变化及重力时变序列,并模拟青海玛多地震同震重力变化,以探索涵盖此次地震震中的大尺度重力变化背景及可能存在的孕震信息。研究结果表明:1)研究区域长期重力变化趋势的范围为-1~1μGal·a^(-1),重力变化长期呈现出负—正—负—正的大四象限空间布局;2)云南漾濞地震及青海玛多地震均位于重力变化四象限分布的低值区及高梯度带的拐角处,这与地表重力地点预测的基本特征一致;3)2002年以来的M S≥7.0地震,如汶川地震、玉树地震、芦山地震、九寨沟地震、玛多地震、尼泊尔地震等都发生在该四象限分布的中心区域或与构造相关的高梯度带的拐角处,这与地面重力地震预测的震例经验吻合;4)基于位错理论模拟的青海玛多地震的同震重力变化可达-40~151μGal,重力卫星精度需要提高1~2个量级方能探测到这一变化。重力卫星星座的搭建将为提高卫星重力地震监测能力提供可能。The Yangbi M_(S)6.4 earthquake in Yunnan Province and Maduo M_(S)7.4 earthquake in Qinghai Province occurred in western China on May 21 and May 22,2021,respectively,which caused huge loss of life and property.Gravity changes in the epicentral area and its surroundings before the two earthquakes can provide important reference for studying the seismogenic environment and background.The ground gravity observation is relatively sparse in western China and satellite gravity can supplement this deficiency.GRACE(Gravity Recovery and Climate Experiment)(from March 2002 to June 2017)and GRACE-FO(GRACE Follow-on)(from May 2018 to March 2021)can produce the wide-area space,quasi-real-time,long-term and near-continuous observation data,which will provide large-scale background information for the ground gravity research.In this paper,the epicenters of the two earthquakes and their surrounding area were taken as the study area(18°~45°N,83°~115°E).We used GRACE,GRACE-FO and GLDAS(Global Land Data Assimilation System)data to calculate long-term gravity spatial-temporal distribution in the study area with 300km fan filter.We presented the gravity rate,cumulative gravity changes,differential gravity changes in the study area for about 20 years,and the gravity time series of Maduo earthquake and Yangbi earthquake.We simulated the theoretical co-seismic gravity variation of Maduo earthquake and evaluated the possibility of detecting the co-seismic gravity signal for GRACE-FO.The research results showed that:(1)Long-term gravity changes in the study area were mainly characterized by positive-negative-positive-negative spatial layout in four quadrants.Gravity increased in Qinghai-Tibet block and South China block,and gravity decreased in Indian block and North China block.However,the North-South seismic belt and Bayankala block were located at the low-value areas in four quadrants and their gravity changes were relatively small.This was the large-scale gravity seismogenic background in western China.(2)The epicenters of Maduo ea

关 键 词：重力卫星 位错理论 重力变化 地震 GLDAS 

分 类 号：P315.726[天文地球—地震学]