汶川M_S8.0地震前后川滇地区地壳水平形变动态变化初探  

Dynamic Variation of Horizontal Crustal Deformation in the SichuanYunnan Region before and after the Wenchuan M_S8.0 Earthquake

作　　者：党学会[1] 王同庆[1] 吕志鹏[1] 申星[1] 

机构地区：[1]中国地震局第一监测中心,天津300180

出　　处：《地震工程学报》2016年第A01期30-35,共6页China Earthquake Engineering Journal

基　　金：地震科技星火计划项目青年项目(XH15061Y);中国地震局震情跟踪青年课题(2015010220);中国地震局第一监测中心科技创新主任基金(FMC2014012)

摘　　要：利用中国地壳运动观测网络和中国大陆构造环境监测网络GPS区域网观测资料,解算川滇地区1999—2007年、2009—2011年相对欧亚板块的水平速度场,并借助连续应变模型获得了川滇地区应变率场。通过分析汶川地震前后地壳水平运动速度场和应变率场的动态变化,得到:(1)水平相对运动与主应变场分布反映出在巴彦喀拉地块的东向推挤与华南地块的强烈阻挡下,龙门山断裂带长期的应力应变积累并突然释放导致了汶川大地震的发生;(2)发生大地震的龙门山断裂带在地震前应变量值并不显著,处于应变亏损状态,应变高值区主要集中在川滇菱形块体的东边界与北边界;(3)大地震的发生导致震源区及其周边应力应变剧烈调整,龙门山断裂带中南段显示出明显的应变增强态势,一定程度上反映了2013年芦山7.0地震发生前的应变背景累积信息。By analyzing the GPS data collected from the Crustal Movement Observation Network in China, we derive the horizontal velocity field of the Sichuan - Yunnan region during 1999- 2007 and 2009-2011. Based on the results of the horizontal velocity field, we also obtain thestrain-rate field of the Sichuan- Yunnan region using a continuous strain model. Through an analysis that considers the seismo-tectonic background and the horizontal crustal movement in the study area, as well as the dynamic change in the strain-rate field before and aMs8.0 earthquake, this paper studies inter-seismic crustal deformation in the region, discusses the active tectonic and geodynamic model that caused the inter-seismic deformation, and analyzes the mechanisms that led to the Wenchuan earthquake. The conclusions could help in understanding the dynamic variation of horizontal crustal deformation in the Sichuan- Yunnan region before and after this particular earthquake.

关 键 词：GPS 川滇地区 应变场 水平形变 

分 类 号：P315.725[天文地球—地震学]