Abstract:
Surface subsidence is a major geological hazard in the North China Plain (NCP), severely hindering the regional sustainable development. As an important part of the NCP, the northern Henan area has experienced increasingly severe surface subsidence in recent years due to rapid economic growth and groundwater over-exploitation. However, the fine-scale spatiotemporal patterns and dominant driving factors of surface subsidence in this area remain poorly understood. Based on Sentinel-1A synthetic aperture radar (SAR) imagery from January 2021 to June 2025, this study achieved high-precision, long-term monitoring of surface subsidence in northern Henan using the small baseline subset-interferometric synthetic aperture radar (SBAS-InSAR) technique. The monitoring results were further cross-validated based on Global Navigation Satellite System (GNSS) observations and examined via internal coincidence accuracy analysis, confirming their reliability. By combining contemporaneous groundwater level and precipitation data, this study investigated the evolutionary patterns and driving mechanisms of surface subsidence in two areas: the Anyang-Neihuang boundary area (subsidence area 1, an agricultural area) and Taiqian County in Puyang (subsidence area 2, an industrial area). The results indicate that subsidence area 1 exhibited a step-like subsidence pattern regulated by precipitation. Such a pattern is linked to the groundwater level, presenting distinct seasonality and hysteresis effects. In contrast, subsidence area 2 formed a typical subsidence funnel, with an evolutionary pattern consistent with industrial groundwater exploitation. This finding suggests that anthropogenic factors predominate in subsidence area 2, with limited influence of precipitation. Furthermore, the study quantified the contribution weights of various driving factors using a support vector regression (SVR) model, identifying groundwater exploitation as the dominant factor. The results of this study reveal the differential subsidence mechanisms consisting of natural and anthropogenic driving factors across different land use types. This study provides a scientific basis for the prevention and control of surface subsidence, along with the implementation of groundwater management strategies for specific land use types in northern Henan.