PS-InSAR based surface subsidence analysis in Changchun metropolitan area

The monitoring of urban land surface subsidence is the main task of urban disaster prevention and mitigation. In this paper, the land surface subsidence process in Changchun metropolitan area is calculated based on PS-InSAR technology by using the SLC data of Sentinel-1B with 50 scenes within the metropolitan area of Changchun from 2016 to 2020. The results show that the metropolitan surface of Changchun is basically in a stable state, the main settlement is located in the southeast of the metropolitan around the Century Square, the maximum settlement rate is 20.45mm/a, the average settlement rate is 2.98mm/a, the correlation coefficient between the settlement results calculated by PS-InSAR and the second-class leveling verification results reaches 0.67, which indicates that the regional settlement results calculated by PS-InSAR have high reliability. The subsidence area is dominated by the geological structure of the Mesozoic Cretaceous Yaojia Formation, with many intercalations of fine silty sand rocks and locally containing medium-coarse gravel sandstone. The overall structural stability is poor, which may be the main reason for subsidence in this area