关键词: 遥感图像, 活动构造, 焉耆盆地

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