长江三峡库区地震地形变监测研究

CRUSTAL DEFORMATION OF THREE GORGES AREA

三峡地壳形变监测网络结合空间大地测量 (GPS、InSAR)和传统大地测量的优点 ,在 1998年以来的三峡工程建设期间和 2 0 0 3年水库首次蓄水中获取了大量监测成果。结果显示库区地壳运动的基本图像 :垂直形变较为显著 ,主要来自因蓄水荷载而产生的形变 ,水平形变不明显 ,库区主要断层的活动性在蓄水期间有明显加强迹象。水准测量反映从 1998年首期观测至 2 0 0 3年 10月首次蓄水后的库区垂直位移 ,沉降范围较大 ;GPS给出了2 0 0 3年蓄水前后库区的垂直位移 ,形变的范围主要集中在水库近岸区域。水准测量与GPS观测反应的垂直位移的量级基本一致 ,沉降的最大幅度在 3～ 4cm左右。水准监测、GPS观测与重力监测结果有一定的对应性。从地壳形变监测与研究结果分析 。

A good number of monitoring data has already been obtained by the crustal deformation network of the Three Gorges reservoir-induced earthquake monitoring system combined with space geodesy ,such as GPS and InSAR, and the traditional geodesy since 1998, especially during reservoir impounding in 2003.These data show the basic characters of crustal deformation in the Three Gorges reservoir area,which includes:the vertical subsidence is substantial and the horizontal deformation is modest, the activity of the main faults in the reservoir area has been intensified during reservoir impounding.In addition,leveling data shows that there was a large vertical displacement from 1998 to the first reservoir impounding in 2003.And GPS data shows that the vertical deformation is mainly located in shore of the reservoir before and after impoundment.The magnitudes of vertical displacement surveyed by leveling and GPS are consistent with each other and the maximum value is about 3-4 cm. Leveling, GPS and Gravity observations are corresponding to each other. According to the crustal deformation observation data and analysis, the induced earthquake caused by water load change would not likely to occur in the near future.