川滇地区地壳块体运动特征研究*

(中国地震局第二监测中心,陕西 西安 710054)

均匀弹性块体应变模型; GPS; 地壳运动; 川滇地区

Research on the Characteristics of Crustal Block Movement in Sichuan-Yunnan Area
JIANG Feng-yun,ZHU Liang-yu,WANG Shuang-xu,ZHANG Xiao-liang,

(The Second Crust Monitoring and Application Center,CEA,Xi'an 710054,China)

homogeneous elastic strain block model; GPS; crustal movement; Sichuan-Yunnan region

备注

通过对川滇地区块体细划,借助均匀弹性块体应变模型,利用 1999~2007年和2009~2011年两个时段GPS观测地壳水平运动场,计算了这两个时间段该区块体应变状态、块体内部均匀弹性变形场及相邻块体边界带的相对运动。考虑汶川地震、玉树地震对该区域的地壳运动的影响,分析计算结果认为:(1)计算结果较好地反映了该区域构造运动特征;(2)川滇地区块体东边界运动主要以走滑为主,安宁河断裂和则木河断裂的交汇部位表现为明显的左旋走滑运动受阻,且其两侧块体应变率积累显著,是未来可能的强震孕育区;(3)2009~2011年与2007~2009年相比,整个区域块体边界运动空间差异增强,可能反映了汶川、玉树地震对该区域地壳运动的影响。

Based on the division of Sichuan-Yunnan area,using the horizontal crustal movement velocity field by GPS measurements during 1999 to 2007 and 2009 to 2011,we calculated the state of block strain,the homogeneous elastic deformation of the internal blocks and relative motion of the boundary between the adjacent blocks by the homogeneous elastic strain block model. Considering the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on crustal movement of Sichuan-Yunnan area,the calculation analysis results showed that:(1)The calculation results reflected the better characteristics of tectonic movement in the region;(2)The movement of the east boundary on Sichuan-yunan block mainly was strike-slip. The intersections of An'ninghe and Zemuhe Faults showed that the left-lateral strike-slip movement was blocked apparently,and there were significant strain accumulation in the block on both sides of this site,which indicated it maybe the area of possible strong earthquakes preparation in the future;(3)The spatial differences of the blocks boundary movement were enhanced in 2009~2011 than that in 2007~2009,which reflects the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on the regional crustal movement in the whole area.