Subsidence Detection by PSInSAR Based on High Resolution TerraSAR-X Images

摘要

Land subsidence is a major concern for land use planning and geological risk assessment. Here we describe a persistent scatterer interferometric synthetic aperture radar (PSInSAR) method for subsidence detection. The Jinghai County in Tianjin (China) is selected as the study area, which has been sinking due to the overuse of groundwater. The time series of high resolution SAR images collected by the X-band radar sensor onboard the satellite TerraSARX (TX) are utilized for the PS detection, PS networking and subsidence estimation. The test results show that the high resolution of TX SAR images can dramatically increase the PS density, especially in the built-up areas. Subsidence information can be extracted on the individual objects like buildings, street lamps and manhole covers, and on the linear engineering structures like the Jinghu high speed railway. The TX PSInSAR with short radar wavelength (3.1cm) is quite sensitive to vertical motion, and the derived subsidence measurements are in good agreement with the in situ data taken by optical leveling.