基于GNSS的红河断裂中段现今变形特征  

Present-Day Deformation Characteristics of the Central Segment of the Red River Fault Based on GNSS

作　　者：黄勇 孟国杰[1] 吴伟伟[1] 程旭[1] HUANG Yong;MENG Guojie;WU Weiwei;CHENG Xu(Institute of Earthquake Forecasting,CEA,63 Fuxing Road,Beijing 100036,China;Institute of Seismology,CEA,40 Hongshance Road,Wuhan 430071,China)

机构地区：[1]中国地震局地震预测研究所,北京市100036 [2]中国地震局地震研究所,武汉市430071

出　　处：《大地测量与地球动力学》2024年第1期57-62,共6页Journal of Geodesy and Geodynamics

基　　金：国家重点研发计划(2019YFE0108900);国家自然科学基金(41874024);中国地震局地震预测研究所专项基金(CEAIEF20220404);中国科学院精密测量科学与技术创新研究院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：采用红河断裂带中段加密布设的GNSS连续站观测资料以及前人发布的速度场结果,获取红河断裂带中段及邻区现今地壳运动速度场。根据川滇地区活动断裂分布建立研究区三维有限元模型,以红河断裂带中段及邻区GNSS速度场为约束,获得红河断裂带中段不同段落的现今滑动速率和区域应变率场。结果表明,红河断裂带弥渡-元江段右旋走滑速率为1.2±0.6 mm/a,挤压速率为0.6±0.5 mm/a;红河断裂带元江-元阳段右旋走滑速率为1.8±0.7 mm/a,挤压速率为1.5±0.6 mm/a。应变率结果显示,红河断裂带中段及邻区以剪切变形为主,最大剪应变率高值区位于小江断裂带附近,最大幅度约为62×10^(-9)/a,红河断裂剪切变形相对较弱;面应变率显示,红河断裂元江-元阳段挤压变形较为显著,挤压应变率值约为10×10^(-9)/a,该段落处于强闭锁状态,未来地震危险性值得关注。We obtain the velocity field of present-day crustal motion of the central segment of the Red river fault and adjacent region by using the encrypted GNSS stations and previously published velocity field data.The three-dimensional finite element model of the study area is constructed based on the distribution of active fault in the Sichuan-Yunnan region.We obtain the fault slip rate of different sections of the central segment of Red river fault and strain rate field of study area constrained by GNSS velocities.The results show that the Midu-Yuanjiang segment of Red river fault experiences a right-lateral slip rate of 1.2±0.6 mm/a and a shortening rate of 0.6±0.5 mm/a,and the Yuanjiang-Yuanyang segment of Red river fault experiences right-lateral slip rate of 1.8±0.7 mm/a and a shortening rate of 1.5±0.6 mm/a.The strain rate results show that shear deformation dominates in the central segment of the Red river fault and adjacent region.The maximum shear strain rate appears in the Xiaojiang fault zone with a rate of about 62×10^(-9)/a;the shear deformation is relatively weak along the Red river fault.The dilatation strain rate shows that compressive deformation is significant along the Yuanjiang-Yuanyang segment of Red river fault with the rate of about 10×10^(-9)/a.There is strong coupling along the Yuanjiang-Yuanyang segment,and the seismic hazard of the Yuanjiang-Yuanyang segment deserves more attention.

关 键 词：红河断裂中段 GNSS速度场 有限元模拟 断层滑动速率 应变率场 

分 类 号：P315[天文地球—地震学] P228[天文地球—固体地球物理学]