Radar Interferometry for Urban Subsidence Monitoring

Due to the rapid growth of economy in China, the amount of water usage has increased dramatically in many major cities. The over exploitation of underground water in the north region of China causes severe urban subsidence over last 3 decades. The conventional surveying methods have been used to monitor the subsidence. It is, however, very challenging to identify the coverage of the subsidence basin and to set up the bench marks for the ground survey. It is also very time consuming and labour intensive to have dense survey marks over a large area. Therefore, differential radar interferometry is used here as a complementary technique. Both conventional 2-pass differential interferometric synthetic aperture radar (DInSAR) and advanced DInSAR using coherent targets were tested with JERS-1 data for monitoring urban subsidence in this paper. The multi-temporal differential interferograms revealed the magnitude and coverage of the subsidence. In summary, the total subsidence over the period of January 1995 to July 1998 is over 25cm, which is about 7.3cm/year. The feasibility of using coherent targets for the same region is also discussed. Index Terms – DInSAR, Urban Subsidence, JERS-1