Monitoring Surface Deformation in Xi’an City from 2019 to 2022 Based on Sentinel-1A Data

Xi’an is one of the areas in China where geological hazards such as ground subsidence and ground fissures are concentrated and developed. Ground subsidence in Xi’an is closely related to groundwater over–extraction. In recent years, groundwater levels have recovered as a result of the ongoing artificial recharge of groundwater in Xi’an. In this paper, 47 scenes of Sentinel-1A data from January 2019 to August 2022 in the urban area of Xi’an were processed using the small baseline subset InSAR technique to obtain the latest ground deformation characteristics of the Xi’an area. The main results obtained in this paper are as follows: with the groundwater level starting to rebound, ground subsidence in Xi’an has now been effectively alleviated, and ground rebound has been observed in typical subsidence areas such as Yuyuanzhai and Electronic City, etc. Extensive ground subsidence is hardly visible, and only scattered subsidence areas are seen in the southeast of the urban area. Changes in the groundwater table are an important cause of ground rebound. The surface uplift deformation in both the Electronic City area and the Yuhuazhai area has already passed the elastic deformation period of rapid soil deformation. The overall amount of rebound is within the safe range and the impact on the surrounding metro and buildings is limited.