Ground Deformation Monitoring in Tongzhou Based on High Resolution SAR Images

Abstract

D-InSAR technique based on time series of SAR images has been very popular to monitor ground slow deformation in recent years, such as Permanent Scatterers (PS) method, small baseline subsets (SBAS) method, and coherent targets (CT) method. By taking advantage of PS method and CT method, in this paper, small baseline and Permanent Scatterers D-InSAR technique are used to investigate the ground deformation of Tongzhou district in Beijing City, from January 4, 2009 to August 14, 2011 by using 21 COSMO-SkyMed single complex images. The experiment results demonstrate that the two methods of SBAS and PS technique have high consistency in the trends of ground deformation and the time series of deformation value according to choosing some latitude and longitude of the same points, and the deformation rate respectively reaches -7 cm/year and 4 cm/year; during this period, four significant subsidence centers have been developed in Tongzhou district, namely SanJianfang town, Jinzhan town, Songzhuang town and Tongzhou city center. The largest subsidence center is SanJianfang town with an average subsidence rate of −4.7 cm/year, the center of deformation area of SanJianfang town and Tongzhou district are more and more obvious expansion and polymerization. The subsidence of the old center, Wangsiying, has slowed down, and the subsidence in the western region has stopped and some areas even rebounded, and the possible cause for the ground deformation is groundwater extraction.