摘要
基于1999～2007年和2007～2009年的GPS站点观测数据计算的速度场,分析了青藏亚板块的运动特征.利用块体(旋转与线性应变)弹性运动公式计算可可西里—巴颜喀拉块体和羌唐块体的应变率、可可西里—玉树断裂带的运动速度和应变率,研究了玉树7.1级地震前的形变应变特征.结果表明:可可西里—巴颜喀拉块体处于青藏亚板块运动场的差异变化较大的地带;1999～2007年可可西里—玉树断裂带左旋走滑运动为主;2007～2009年可可西里—玉树断裂带在玉树以西压应变率显著增强,利于应力积累,以东为右旋为主,玉树附近地段成为不同应变应力状态的转换地带——不稳定地段.可可西里—玉树断裂带的活动为7.1级地震孕育提供了能量积累和发震条件.
t Base on the velocity field calculated from the GPS data from 1999 to 2007 and from 2007 to 2009,the movement characteristics of Qinghai-Tibet subplates were studied. The strain rate of Hob Xil-Bayan Har block and the Qiangtang block, the velocity and the strain rate of Hob Xil-Yushu fault zone were calculated by the block （rotation and linear stain） elastic movement formula. The deformation strain before Ms7. 1 Yushu earthquake has been studied. The result shows that between 1999 and 2007 the activity in Yushu fault zone was mostly left-lateral strike slip. Between 2007 and 2009, the strain rate of Hoh Xil-Yushu fault zone in the western part of Yushu has increased remarkably, which is favorable to stress accumulation. The Hoh Xil-Yushu fault zone in the eastern part of Yushu showed mainly right-lateral strike slip activity. Yushu was a transitional area between different kinds of active strain and became an unstable zone. The activity in Hob Xil-Yushu fault zone became a condition of the Ms7.1 earthquake, in the meantime,accumulated energy for the earthquake.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第8期1990-1996,共7页
Chinese Journal of Geophysics
基金
天津市应用基础研究(08JCZDJC18900)
中国地震局"全国地震区划图编制项目"资助
关键词
GPS运动场
块体运动
断裂带活动
应变率增加
玉树地震孕育
Movement field of GPS, Movement of block,Activity of fault zone,Increase of strainrates,Development and occurrence of Yushu earthquake
