Monitoring and analysis of land subsidence on the east bank of Erhai Lake based on SBAS-InSAR and GNSS technologies
Abstract
Haidong New City district, located on the east bank of Erhai Lake in Dali, is characterized by complex topography and significant mountainous relief. Over the past decade, extensive urban development and construction have substantially altered and disrupted the original geomorphology, resulting in multiple potential geological hazard sites across the new district, including land subsidence, landslides, and ground deformation. This paper focuses on elucidating the spatial distribution and intrinsic causative mechanisms of land subsidence in the Haidong New City district. We acquired 75 ascending and 77 descending Sentinel-1A SLC images. The Small Baseline Subset Synthetic Aperture Radar Interferometry (SBAS-InSAR) technique was employed to calculate and analyze land subsidence rates and time-series deformation. Furthermore, Global Navigation Satellite System (GNSS) monitoring data were utilized to validate the InSAR-derived subsidence results. Through a comparative analysis, this paper summarizes the temporal evolution of land subsidence over the past five years and investigates its underlying causes in the subsidence-prone areas of Haidong New City district. The findings provide a scientific basis for future urban development planning and the prevention and control of subsidence-related disasters in the region.