Spatial and temporal evolution characteristics of land subsidence in Fuyang: time series InSAR monitoring and analysis of impacting factors

Fuyang has been significantly affected by severe land subsidence hazards, prompting an urgent assessment of its current subsidence status and the underlying contributing factors. This study investigates the spatial and temporal evolution of land subsidence in the Fuyang urban district by employing time series InSAR techniques and analyzing 153 scenes of Sentinel-1 image acquired between 2017 and 2023. Additionally, the study explores the factors influencing land subsidence in the Fuyang urban district by the Geodetector from the perspectives of both natural environment and anthropogenic activities. Results indicated that: (1) Overall, land subsidence in the Fuyang urban district from 2017 to 2023 is relatively minimal, with some certain areas being more serious. Land subsidence in the Fuyang urban district is mainly distributed in zones of urban development and agricultural cultivation, with less pronounced subsidence in the old urban district. Two subsidence patterns have been observed: rapid initial subsidence followed by deceleration, and sustained steady subsidence. (2) Human activities have a significant impact, with road network density, NDVI, and population density identified as the primary influencing factors. The interactions among these factors exhibit enhancement and nonlinear enhancement effects, with the most interactions observed between human activity factors. The rate of land subsidence is the highest within the urban construction land area and is further exacerbated by urban expansion. (3) The Geodetector performs effectively in identifying the influencing factors and interactions related to land subsidence, with results showing strong interpretability. It is suggested that the method can be further applied and promoted in future studies. The results are significant for clarifying the current state of land subsidence in the Fuyang urban district and identifying its underlying causes. They also provide a valuable reference for the formulation of scientifically sound urban planning, sustainable resource management, and targeted subsidence mitigation measures in Fuyang.