Land subsidence detection and analysis over Chongqing based on Sentinel-1A TS-InSAR

Chongqing is the largest mountain city in the world and has suffered subsidence problems because of its rapid development. However, time series and wide range subsidence monitoring in Chongqing was lacking. In order to study the subsidence spatial distribution and subsidence temporal changes in Chongqing, this paper employed the Time-Series Interferometry Synthetic Aperture Radar (TS-InSAR) and Sentinel-1A images acquired between 2017 and 2019 to derive subsidence in Chongqing. And used POD Precise Orbit Ephemerides and ASTER GDEM V2 to remove the phase jump caused by spectral decorrelation between bursts. Results show that: Chongqing has four main subsidence areas: two subsidence bands (P1 and P2 areas) through the city from north to south, and two subsidence areas distributed in the Nanan district (P3 area) and Jiangbei District (P4 area). Among them, the maximum deformation rate has reached −22.45 mm/year, and the maximum deformation of land subsidence has reached −59.50 mm. Besides, due to the complex of the mountain city's geological environment, it is expected that the subsidence difference for the Chongqing city is getting bigger and bigger.