Abstract: Urban ground subsidence can lead to building cracks and tilting, damage to underground infrastructure, and secondary disasters, posing a serious threat to the sustainable development of cities. Therefore, accurately understanding the spatiotemporal evolution characteristics of ground subsidence and identifying its dominant driving mechanisms are of great significance for developing effective monitoring strategies and mitigation measures. This study utilized the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique and analyzed 154 scenes of Sentinel-1A satellite imagery from January 2020 to March 2025 to obtain the spatiotemporal distribution characteristics of ground subsidence in the central urban area of Ganzhou City. The results show that 80% of the study area has subsidence rates between -2 and 2 mm/y; localized areas exhibit significant subsidence, primarily concentrated in Ganzhou County , with the highest annual average subsidence rate reaching -26.4 mm/y. Some subsidence centers exhibit distinct seasonal fluctuations, primarily influenced by variations in precipitation infiltration recharge and the intensity of groundwater extraction. Additionally, human activities such as the perturbation of the new construction loads and river sediment deposition also triggered significant ground subsidence in localized areas. This study contributes to understanding the spatiotemporal evolution characteristics of ground subsidence in Ganzhou City, further optimizes urban ground subsidence monitoring methods, and provides scientific support for enhancing the city’s geological hazard risk management capabilities.

Key words: SBAS-InSAR, land subsidence, time series analysis, Ganzhou City