Abstract: Tian Shan, an intracontinental orogenic belt formed in the late Paleozoic, has been reactivated since the India-Eurasia collision in the Eocene. Active tectonics are widespread in and around Tian Shan, and they are of great significance to the understanding of the effect of India-Eurasia collision and the seismic hazard assessment of this region. Conventional geological investigation is very difficult to be carried out in this region, since the most areas of the range are difficult of access. We employed satellite remote sensing data, therefore, to identify the distribution of active tectonics and their deformation features in these areas. In addition, a selected field study was carried out in Yanqi basin in order to verify the interpretation and analysis results of remote sensing data and to get some ground truths. Yanqi Basin is one of the Mesozoic-Cenozoic intermontane basins in the southeastern Tian Shan. The features of active tectonics in the western part of the basin can easily be recognized on remote sensing images, such as distinct linear structures, offset gullies, and left-stepping en echelon arrangement of fault scarps. The active tectonics are composed of the active folds in the northwestern part of the basin and active right lateral strike-slip faults in the southwestern part of the basin. The results of fieldwork are coincident with the imagery interpretation, indicating that the remote sensing technique is a very powerful, rapid and low-cost way to research active tectonics in the region with poor vegetation and traffic conditions. The maximum displacement of offset gullies along the fault is 210m with a vertical component of 20m, indicating that strike-slip is predominant. The well developed active tectonics in the Tian Shan reveals that the collision between the Indian and Eurasian continents is still continuing.

Key words: remote sensing images, active tectonics, Yanqi basin

摘要： 焉耆盆地是一个位于天山东南部的山间盆地,在遥感图像上,可以看到盆地西面的活动构造在地表留下的痕迹:清楚的线形构造,被错开的水系、冲沟等。经分析认为,这些活动构造主要由北边的活动褶皱和南边的右行走滑活动断裂组成。野外的实际调查与图像分析的结果十分吻合,表明遥感图像在研究活动构造方面是一个十分有力和快速的工具。活动断层的最大水平位移为210m,最大垂直位移为20m,主要以走滑作用为主。天山地区活动构造的发育表明印度板块向欧亚板块的碰撞仍在持续。

关键词: 遥感图像, 活动构造, 焉耆盆地