强震造成的活动地块地壳形变差异探讨  

DIFFERENCE OF CRUSTAL DEFORMATION IN ACTIVE BLOCKS CAUSED BY GREAT-EARTHQUAKES

作　　者：唐方头[1] 张培震[1] 邓志辉[1] 

机构地区：[1]中国地震局地质研究所,北京100029

出　　处：《地震地质》2003年第4期655-663,共9页Seismology and Geology

基　　金：国家重点基础研究发展规划项目 (95 130 5 0 3);国家自然科学基金 (4 0 2 74 0 34)资助

摘　　要：20 0 1年 11月 14日发生在昆仑山口西的 8 1级地震 ,在地表产生了长度大于 35 0km的破裂带 ,最大水平位移 6m左右 ,为左旋走滑断层。在昆仑山口西 8 1级地震周围不同活动地块内不同构造部位布设的GPS基准站对地震的响应存在明显的差异。其中位于柴达木活动地块内部的德令哈基准站在地震的当天观测到 7 5mm的同震位移 ,位于川滇活动地块西南边界带的下关基准站在震后 3d发生了 6 8mm以上的明显位移 ,而位于同一地块内部的昆明基准站和位于祁连山活动地块内的西宁基准站、位于拉萨活动地块内的拉萨基准站震时和震后都没有产生明显的位移。GPS基准站的观测资料表明 ,强震所处的活动地块和其相邻活动地块对强震有明显的响应 ,如果相隔一活动地块 ,则受强震的影响较小 ;在活动地块内 ,活动强烈的边界带或其它活动较强的部位对强震引起的地壳形变的响应明显大于活动强度较弱的部位 ;强震对相邻活动地块影响的差异 ,主要与强震所处活动地块运动时对其产生的作用方式的差异有关。The most remarkable feature of Cenozoic and present day tectonic deformation of the continental lithosphere of China is that the crust has been cut by huge late Quaternary active faults, forming active crustal blocks of different orders. Various active crustal blocks exhibit different horizontal movement and different deformation styles. The inner part of the active crustal block is relatively stable. Deformation commonly takes places along their boundary structures, and most of the great earthquakes ( M ≥7) occur along these boundaries. In order to monitor crustal movement in China mainland, China Crustal Movement Observation Network has disposed 25 continuous GPS base stations in the main tectonic units all over the country. These stations had been run for 3 years from March 1999 to December 2001. On 14 Nov. 2001, an earthquake of M S 8.1 occurred to the west of the Kunlun Mountain Pass. This event has produced a surface rupture zone of more than 350km in length with a general strike of 70°～90°. The rupture zone is dominated by left lateral strike slipping, and the largest horizontal displacement is about 6m. The observation data of continuous GPS measurement stations show that various GPS stations in different active blocks around this earthquake site had different responses to the earthquake. The GPS station within the active block where the earthquake occurred, such as the Delingha station, exhibited very obvious displacement. However, no obvious displacement was observed at the GPS stations located in the active blocks that are secluded by one active block from the earthquake site,such as the Lhasa GPS station. If the GPS stations are located on the boundary structures of the active blocks adjacent to the earthquake site, such as the Xiaguan GPS station, then they would record obvious displacements several days after the occurrence of the earthquake. If the stations are located within the active blocks, such as the Xining and Kunming GPS stations, no obvious displacement would be observed

关 键 词：强震 活动地块 地壳形变 GPS基准站 位移时间序列曲线 

分 类 号：P315.2[天文地球—地震学] P228.4[天文地球—固体地球物理学]