川滇地区地壳应力场研究现状  

Research actuality of crustal stress field in the Sichuan-Yunnan region

作　　者：田建慧 高原[1] TIAN JianHui;GAO Yuan(Key Laboratory of Earthquake Prediction,Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Beijing Earthquake Administration,Beijing 100080,China)

机构地区：[1]中国地震局地震预测研究所(地震预测重点实验室),北京100036 [2]北京市地震局,北京100080

出　　处：《地球物理学报》2024年第9期3436-3453,共18页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42330311,42074065);中国地震局地震预测研究所基本科研业务费专项(2021IEF0103)共同资助。

摘　　要：位于青藏高原东缘的川滇地区不仅是印度板块与欧亚大陆挤压碰撞的前缘地带,也是研究青藏高原演化以及高原物质东南向逃逸的重要场所,区域地壳被纵横交错的活动断裂和块体边界切割为多个次级块体,剧烈的构造运动导致了该区应力场具有强烈的横向不均匀分布.本文总结了近年来川滇地区地壳应力场研究进展,分析了地表变形场、原地应力测量资料、震源机制解结果,系统讨论了川滇地区不同尺度的应力场方向及非均匀性特征.川滇地区的地表变形场沿鲜水河—小江断裂带为界的西侧区域,到红河断裂与丽江—小金河断裂交汇区域,都为明显的顺时针旋转变形.在青藏高原物质东向挤压作用下,川滇地区的构造应力场整体以龙门山断裂—丽江—小金河断裂为界,北部以NE-SW、E-W向挤压和NW-SE、N-S向拉张为主,南侧主压应力沿该断裂带呈扇形分布,与地表变形场形态一致,主张应力沿该断裂系呈弧形分布,与地形等值线特征基本一致.川滇地区的壳幔变形可能是北部耦合,南部解耦.本文分析发现,区域内龙门山断裂、红河断裂和丽江—小金河断裂等大型断裂带下方构造应力场呈现分段变化,与地震各向异性揭示的深部介质变形有关.The Sichuan-Yunnan region,located in the eastern margin of the Tibetan Plateau,is not only the foreland of the collision between the Indian and the Eurasian plates,but also an important site for the study of crustal deformation and the eastward escape of plateau materials.The regional crust is cut into multiple secondary blocks by crisscross active faults and block boundaries.Severe tectonic movements have caused strong lateral inhomogeneity in the stress field.This paper provides a systematic summary of recent research progress on the stress field in the Sichuan-Yunnan region.By analyzing the results of surface deformation field,in-suit stress measurement,and focal mechanism solution,the paper presents an in-depth analysis of the stress field direction and heterogeneity characteristics of different scales.The surface deformation field in the Sichuan-Yunnan region along the Xianshuihe-Xiaojiang fault as the boundary of the western region,to the intersection area of Red River fault and Lijiang-Xiaojinhe fault,are obvious clockwise rotation deformation.Under the eastward compression of the Tibetan Plateau,the stress field in the region is bounded by the Longmenshan fault-Lijiang-Xiaojinhe fault,with the north side dominated by NE-SW,E-W compression and NW-SE,N-S tension.The principal compressive stress on the south side is fan-shaped along the fault,basically consistent with the surface deformation field,while the principal tensile stress is arc-shaped along the fault,basically consistent with the contour shape of the terrain.At the same time,the crust-mantle deformation in the Sichuan-Yunnan region may be coupled in the north and decoupled in the south.In this paper,it is found that the tectonic stress field under the large fault zone,such as Longmenshan fault,Red River fault and Lijiang-Xiaojinhe fault shows a segmented variation,which is related to the deformation of deep media revealed by seismic anisotropy.

关 键 词：川滇地区 构造应力场 地表变形场 龙门山断裂 丽江-小金河断裂 

分 类 号：P542[天文地球—构造地质学] P315[天文地球—地质学]