基于GPS技术的活动断裂监测——以鲜水河、龙门山断裂为例

Monitoring of Faults Activity Based on GPS

GPS作为重要的技术手段,在地壳运动研究中得到广泛应用。以青藏高原东缘的鲜水河、龙门山两条重要活动断裂为例,根据GPS监测获得的欧亚框架的运动速度场,用刚性地块假设下的最小二乘法拟合方法,对其现今断裂活动性进行了研究。研究表明鲜水河断裂、龙门山断裂的整体运动速率分别为8.67±2.65mm/a、1.67±2.07mm/a;鲜水河断裂的甘孜-乾宁段、乾宁-康定段运动速率为8.88±2.74mm/a、9.73±2.30mm/a;龙门山断裂北段、中段、南段运动速率则分别为1.91±2.47mm/a、1.70±0.96mm/a、1.57±1.21mm/a。由此表明鲜水河断裂现今活动性大,而龙门山断裂的活动性相对不大。同时,断裂性质研究表明鲜水河断裂为左旋走滑挤压断裂;龙门山断裂性质为右旋挤压走滑断裂。

GPS was widely applied to research on crusatl motion as a important means. According to velocities field in the Eurasia reference frame, this paper has study the fault activity taking a example of Xianshuihe and Longmenshan active faults on eastern Tibetan Plateau margin by a least square fit under hypotheses of rigid mass. The fitting results shows that：the wholly velocities of Xianshuihe and Longmenshan fault is 8.67±2. 65 mm/a,1.67 ±2.07 mm/a, respectively, to the Xianshuihe fault,The velocity of Gaze-Qianning and Qianning-Kangdin segment is 8.88 ± 2. 74 mm/a,9.73 ±2. 30 mm/a, respectively. To Longmenshan fault, the velocity of northern segment,middle segment and southern segment is 1.91±2.47 mm/a,1.70±0. 96 mm/a,1.57± 1.21 mm/a ,respectively. Therefore, present activity of Xianshuihe fault is stronger than that of Longmenshan fault. Study to fault character also show that ： the nature of Xianshuihe fault is left-lateral strike shp and the nature of Longmenshan fault is right-lateral compressive.