基于震源应力与GPS应变分析喜马拉雅东构造结及其邻区地壳变形特征  

Analysis of the Crustal Deformation of the Eastern Himalayan Syntaxis and Its Adjacent Areas Based on the Earthquake Focal Stress and GPS Strain

作　　者：张晨 季灵运[1] 朱良玉[1] 徐晶[1] ZHANG Chen;JI Lingyun;ZHU Liangyu;XU Jing(The Second Monitoring and Application Center,China Earthquake Administration,Xi'an 710054,Shaanxi,China)

机构地区：[1]中国地震局第二监测中心,陕西西安710054

出　　处：《地震研究》2022年第4期526-534,共9页Journal of Seismological Research

基　　金：国家重点研发计划(2017YFC1500501);国家自然科学基金(42104061);中国地震局地震科技星火计划项目(XH20083)联合资助。

摘　　要：利用1976—2020年喜马拉雅东构造结及邻区M_(L)≥2.0地震的震源机制解反演了研究区域的震源应力场,并结合区域GPS应变率场,分析了该区域现今地壳构造变形特征。结果表明:在川滇菱形块体东边界以及块体内部,最大水平应力SHmax方向与GPS主压应变方向基本一致,且方向变化具有一定的连续性,表明此处上地壳浅部与深部受到相同方向的驱动力;在川滇菱形块体西边界,最大水平应力方向与GPS主压应变呈现出较明显的差异性,分区均值最大可达42°,表明该处上地壳深浅部可能具有不同的驱动机制。This paper uses the focal mechanism solutions of M_(L)≥2.0 earthquakes from 1976 to 2020 to invert the focal stress field in the Eastern Himalayan Syntaxis and its surrounding areas,and uses the GPS strain rate field to analyze the current crustal deformation in this area.The results show that on the eastern boundary of the Sichuan-Yunnan block and inside the block,the direction of the maximum horizontal stress changes continuously,almost in the same direction as GPS principal compressive strain;this indicates that the shallow and the deep parts of the upper Crust are driven by forces in the same direction.On the western boundary of the Sichuan-Yunnan block,the direction of the maximum horizontal stress differs sharply from the direction of GPS principal compressive strain,and the regional average can reach up to 42°;this indicates that different driving mechanisms exist in the deep and the shallow of the upper Crust.

关 键 词：喜马拉雅东构造结 震源机制解 应力场 GPS应变 地壳形变特征 

分 类 号：P313.21[天文地球—固体地球物理学]