青海玛多7.4级地震GNSS同震水平位移的快速获取  

RESEARCH ON FAST ACQUISITION OF GNSS COSEISMIC HORIZONTAL DISPLACEMENT OF MADUO MS7.4 EARTHQUAKE IN QINGHAI PROVINCE

作　　者：李经纬[1,2] 陈长云 占伟[1] 武艳强[1] LI Jing-wei;CHEN Chang-yun;ZHAN Wei;WU Yan-qiang(The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China;Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]中国地震局第一监测中心,天津300180 [2]中国科学院精密测量科学与技术创新研究院,武汉430071

出　　处：《地震地质》2021年第5期1073-1084,共12页Seismology and Geology

基　　金：国家自然科学基金(41974011,11803032);国家重点研发计划项目(2018YFC1503600);中国地震局震情跟踪定向工作任务(20210102225)共同资助。

摘　　要：2021年5月21日青海玛多7.4级地震导致玛多县及其周边地区受灾严重。为了快速获取GNSS同震位移场服务于震情快速研判,文中采用多种方法对玛多地震的同震位移开展了针对性研究。采用1Hz高频动态差分、震后5h静态解算及多天静态解算3种方法获取了同震位移,经对比分析发现GAMIT/GLOBK的动态差分TRACK模块在利用高频数据获取同震形变时适用于近场形变量较大的测站,对远场形变量小的测站则适用性不强;震后5h静态解算获得的同震位移与多天静态解算结果相比时效性更强,两者的数值相差1~4mm,所反映的位移大小、方向及影响范围都保持较强的一致性。综合GNSS资料分析表明,本次地震的发震断层为昆仑山口-江错断裂,且震源机制以左旋走滑为主,距离震中区约40km的QHMD站(青海玛多)的W向位移约为24cm,N向位移约为8cm。从近场震后5h静态解和多天静态解的结果分析可知震后变形显著,仍需持续关注。The May 21,2021,Maduo MS7.4 earthquake in Qinghai Province caused serious disasters in Maduo County and its surrounding areas.The GNSS co-seismic displacement field data can play a key role in quickly determining the influence range of the earthquake and serving for the rapid investigation.After the earthquake,we immediately collected the data of 18 GNSS stations surrounding the epicenter,including 7 stations that recorded 1Hz high-frequency observation data.Various data were used to rapidly obtain the GNSS co-seismic displacements,such as,the 15-minute high-frequency data,5 hours after earthquake and multi-day displacement data.In this paper,we used three methods to obtain the co-seismic displacement,including the dynamic difference method for 1Hz frequency data by GAMIT/GLOBK Track module,and the static difference method for the post-seismic 5-hour data and for the pre-and post-seismic multi-day data by GAMIT/GLOBK.The results are shown as follows:(1)The dynamic difference method for 1Hz frequency data by GAMIT/GLOBK Track module has ability to quickly process the data and acquire the co-seismic displacement.When using the high-frequency data to obtain co-seismic displacement by Track module,it is suitable for the near field stations which have a large value of co-seismic deformation.However,in the far field,the accuracy of the solution is at cm level restricted by the distance of stations.In addition,the result of the Track is influenced by the stability of reference station.Although the results obtained by Track are not accurate,it can be used as a method to quickly judge the characteristics and amount of coseismic surface motion.(2)Comparing the results obtained from the post-seismic 5-hour data and the pre-and post-seismic multi-day data,the GNSS stations’displacements have good consistency in the magnitude,direction and influence range,especially in the near field.The difference of the results by the two methods is from 1mm to 4mm.Considering the processing accuracy of the GAMIT/GLOBK,the value of the di

关 键 词：青海玛多7.4级地震 GNSS 同震位移 

分 类 号：P315.2[天文地球—地震学]