2022年门源6.9级地震的GPS形变特征  

Study of the GPS Deformation Characteristics of the Menyuan M6.9 Earthquake in 2022

作　　者：鲁小飞 谭凯[1,2,3] 张彩红 李琦[1,2,3] 黄勇 李承涛[1,2,3] LU Xiaofei;TAN Kai;ZHANG Caihong;LI Qi;HUANG Yong;LI Cengtao(Institute of Seismology,CEA,40 Hongshance Road,Wuhan 430071,China;Key Laboratory of Earthquake Geodesy,CEA,40 Hongshance Road,Wuhan 430071,China;Hubei Earthquake Agency,48 Hongshance Road,Wuhan 430071,China)

机构地区：[1]中国地震局地震研究所,武汉市430071 [2]中国地震局地震大地测量重点实验室,武汉市430071 [3]湖北省地震局,武汉市430071

出　　处：《大地测量与地球动力学》2023年第4期387-391,共5页Journal of Geodesy and Geodynamics

基　　金：国家重点研发计划(2018YFC1503605);大地测量与地球动力学国家重点实验室开放基金(SKLGED2021-4-1)。

摘　　要：利用1999~2021年的GPS观测资料研究2022年门源6.9级地震震中附近区域的地壳形变特征。速度场在祁连山-海原地震带两侧呈现出明显的“南大北小”特性。发震断层速度剖面结果显示,断层两侧挤压速率为3.1 mm/a,走滑速率为3.9 mm/a,这与走滑为主的震源机制解一致。门源地震位于主应变率场和面膨胀率场高值区向低值区过渡的梯度带上,发生在最大剪应变率场和应变率第二张量不变量高值区边缘地区。同震库仑应力触发了大部分的余震,对冷龙岭断裂到海原断裂的地区有一定的应力加载作用。综合地壳形变特征和库仑应力等分析结果认为,冷龙岭断裂到海原断裂地区的地震危险性有所提高。We use GPS observations from 1999 to 2021 to study the crustal deformation characteristics in the area near the epicenter of the 2022 Menyuan 6.9 magnitude earthquake.The velocity field shows an obvious characteristic of‘big in the south and small in the north’on both sides of the Qilianshan-Haiyuan seismic belt.The results of the velocity profile of the seismogenic fault show that the extrusion rate on both sides of the fault is 3.1 mm/a,the strike-slip rate is 3.9 mm/a.These results are consistent with the strike-slip-dominated focal mechanism solution.This earthquake is in the gradient zone,which transitions from the high-value area to the low-value area of the principal strain rate field and surface expansion rate field.The earthquake occurred at the edge of the high value area of the maximum shear strain rate field and the second tensor invariant of strain rate.The coseismic Coulomb stress triggers most of the aftershocks and has a certain stress loading effect at the area from the Lenglongling fault to the Haiyuan fault.Based on the analysis results of crustal deformation characteristics and Coulomb stress,we think that the seismic risk of the area from the Lenglongling fault to the Haiyuan fault has been certainly improved.

关 键 词：GPS地壳形变 应变率场 门源地震 库仑应力 

分 类 号：P228[天文地球—大地测量学与测量工程] P315[天文地球—测绘科学与技术]