用GPS资料分析渭河盆地及邻近地区地壳运动特征

Analysis of crustal movement feature based on GPS data in Weihe basin and its neighboring region

利用中国地壳运动观测网络工程1999～2002年渭河盆地及邻近地区GPS观测资料,以及陕西省地震局2001～2002年的GPS观测资料,研究了渭河盆地及邻近地区地壳运动速度场。结果表明,渭河盆地及邻区的运动速率有明显的WE向条带状变化特征,鄂尔多斯块体南缘呈整体不连续性逆时针旋转运动,相对鄂尔多斯块体内部的榆林测点,平均速率约为5.7mm/a;渭河盆地中部的彬县—西安—蓝田一线两侧存在一个左旋剪切带(东侧)和右旋剪切带,左旋剪切带的北部区域与铜川—泾阳—临潼—渭南小震频发区恰好对应;鄂尔多斯块体东南缘临汾盆地东侧,GPS观测点资料表现出应力集中的迹象,该区与临汾 韩城地震带也有较好的对应关系。

According to the observed data in Weihe basin and its neighboring region provided by CMONOC during 1999～2002 as well as GPS's data observed by seismological bureau of Shaanxi Province during 2001 and 2002, the authors studies the crustal movement velocity field of Weihe basin and its neighboring region. The characteristics are listed as follows: the movement in Weihe basin and its neighboring region shows obvious bandlike NE direction change. South border of Erdos block shows incontinuous counter-clockwise rotation. Related to Yulin observation site, the movement average rate is about 5.7 mm/1. At two sides of the Binxian-Xi′an-Lantian ray in middle part of Weihe basin exist a left-lateral shear belt (eastern side) and a right-lateral shear belt, and the left-lateral shear belt is just located near the earthquake zone of Tongchuan-Jingyang-Lintong-Weinan. The southeaster margin of Erdos block is to the east of Linfeng basin, it is stress-concentrated region showed by GPS crustal movement data, and it has well corresponding relation to the Linfen-Hancheng earthquake region.