Land Subsidence Monitoring in Nanning Based on Sentinel-1A data and SBAS-InSAR

The Sentinel-1 data is currently the latest free SAR data and is well suited for land subsidence monitoring based on InSAR technology due to its 6-day revisit cycle. The research on the ground subsidence monitoring in mountains city is relative few since the complex topography and high vegetation cover. In this paper, Nanning urban area and its surrounding area are used as the research area, and the time-series surface subsidence monitoring based on Sentinel-1A data and SBAS-InSAR technique is explored. The research shows that most of the regional surface deformation rate is in the range of −8 to 10 mm / a from 2017 to 2019, and the overall cumulative settlement between −15mm and 10mm. Liangqing district is the largest settlement center in Nanning, the maximum average settlement rate in Liangqing subsidence area reaches −20.6 mm/a, and the maximum subsidence is about 40 mm. In addition, the severe settlement area are interconnected with a southeast expansion trend. Additionally, the ground subsidence in study area is influenced by groundwater exploitation and urbanization significantly.