GPS资料揭示的汶川8.0级地震前地壳动态演化特征  

CHARACTERISTICS OF CRUSTAL DYNAMIC EVOLUTION REVEALED BY GPS OBSERVATION BEFORE WENCHUAN 8.0 EARTHQUAKE

作　　者：张晓亮[1] 张希[1] 王双绪[1] 蒋锋云[1] 朱良玉[1] 

机构地区：[1]中国地震局第二监测中心,西安710054

出　　处：《大地测量与地球动力学》2011年第4期1-5,共5页Journal of Geodesy and Geodynamics

基　　金：地震科学联合基金(C08045);中国地震局甘东南-甘青川交界地区强震危险性跟踪分析课题(2009010103)

摘　　要：利用中国大陆1999年以来3个时段的GPS速度场,研究了汶川8.0地震前的地壳动态演化特征。研究结果显示:1)汶川地震发生在区域地壳挤压运动明显受阻的区域,孕震区附近存在一较大的障碍体,震中附近断层多年来处于强闭锁状态;2)随着地震发生日期的临近,震中西侧压性区表现出明显的向东逐步扩张态势,局部地区主压应变方向出现向北偏转,右旋剪切作用明显增强;3)汶川地震同震变形及6级以上余震分布表现出的区段性与断裂带及附近分段性运动变形特征密切相关。By using the GPS velocity fields of China mainland in three time periods since 1999, the character istics of crustal dynamic evolution before Wenchuan Ms8.0 earthquake was studied. From the results following knowledges can be drawn. 1 ）The Wenchuan earthquake had taken place in the zone where crustal squeezed movements were blocked obviously. There was a large obstacle existed in the seismogenic zone, and the fault nearby the epicenter was in strong blocking state for many years. 2） With the Wenchuan earthquake approaching, the compres sive zone in the west to epicenter gradually expanded to east obviously. In some local areas, the direction of princi pal compressive strain deflected northward, and right lateral shear slip enhanced obviously. 3 ）The sectional features of coseismic deformation in Whenchuan earthquake and 6.0 or more aftershock distribution were closely related to the sectional movement deformation of the fault and its vicinal zone.

关 键 词：汶川8.0级地震 GPS速度场 地壳运动变形 断层 动态演化 

分 类 号：P315.726[天文地球—地震学]