Monitoring Ground Subsidence Along the Shanghai Maglev Zone Using TerraSAR-X Images

In this letter, the permanent scatterer interferometric synthetic aperture radar (PS-InSAR) method is applied to extract ground subsidence using X-band TerraSAR-X images. A zone of 1 km width on both sides of the Shanghai maglev was selected, and the ground subsidence rates were obtained on all permanent scatters or highly coherent targets. The results show that permanent scatters are distributed on the rail of the maglev, and the subsidence rates of these PS points are mostly less than 3 mm/a. A KS-test is formulated to judge the agreements between the subsidence results obtained by PS-InSAR and those obtained by spirit leveling, which indicated that PS-InSAR results are acceptable statistically. In addition, the PS-InSAR results show some ground subsiding troughs near the maglev track, with subsidence rates of more than 10 mm/a.