STUDY ON THE CHARACTERISTICS OF BEIJING SUBSIDENCE BASED ON PS-INSAR/LEVELING AND PRIMARY INVESTIGATION OF THE RELATIONSHIP WITH FAULT ZONE

The severe land subsidence could lead to ground collapse, building damage and a series of disasters. Up to now, the land subsidence has occurred in more than 50 cities in China, which seriously affects the life and production safety of local people and restricts the development of cities. While, Beijing is one of the most serious cities. This paper takes the urban area of Beijing as an example. PS-InSAR technology is used to process 40 scenes of Terra SAR images from 2010 to 2015, and the high-coherence points are selected by fusing the two algorithms of coherence coefficient and amplitude deviation. In order to verify the reliability of the results, the second-level measurement results are compared with the PS-InSAR deformation results, and five leveling points are used to evaluate the accuracy. The results show that: the maximum absolute error between the Leveling results and the InSAR measurement result is 8.87 mm, and the standard error is 3.22 mm, which meets the accuracy requirements. And areas with serious subsidence occur in Changping District, Haidian District, Daxing District, and Chaoyang District; there is no obvious subsidence trend in the central and eastern parts of Dongcheng, Xicheng and Fengtai District, and the surface is relatively stable. The subsidence in Tongzhou and Shunyi District is serious relatively, the subsidence in these two areas is -6 mm/a~-67 mm/a and -11 mm/a~-22 mm/a respectively. Finally, the spatial relationship between fault zones and land subsidence was preliminarily discussed. The results show that, the subsidence of the south of Changping was so serious than others while the Nankou-Sunhe fault zone crossed with Babaoshan and Huangzhuang-Gaoliying fault zone through this area respectively