Coupled Multifactor Analysis of Surface Deformation in the Karst Regions of Guangxi Using Time-Series InSAR Monitoring

The Guangxi karst region is highly susceptible to collapse and surface deformation due to its extensive and deeply developed karst systems, posing risks to infrastructure and constraining regional development. In response, the Guangxi government has emphasized integrated management and advanced monitoring technologies, highlighting the need for a wide-area, continuous, and updatable deformation surveillance framework. Yet, long-term, region-scale monitoring and multi-driver coupling analyses remain insufficient. In this study, 691 Sentinel-1A SAR images were processed using SBAS-InSAR to retrieve spatiotemporal deformation across Guangxi from January 2021 to September 2023. Results show deformation rates ranging from −231 to +235 mm/yr, including drought-induced uplift in the northwestern mountains. Farmland uplift in Zuozhou Town is linked to off-site irrigation water transfer, while subsidence in Xingbin District and Maling Town is driven by local groundwater extraction. The Debao and Jingxi earthquakes revealed contrasting deformation patterns—subsidence followed by uplift in plains and uplift followed by subsidence in mountainous terrain. Additionally, 9.06% of fault zones display cumulative deformation markedly above the regional mean, with deformation aligning along structural traces. Periodic deformation is jointly governed by temperature-driven thermoelastic effects and seasonal precipitation, whereas long-term trends are controlled by infiltration-induced hydrological changes. Groundwater levels show a strong positive correlation with deformation (ρ = 0.79). Industrial activity, engineering construction, and mining further induce localized subsidence in Laibin and Baise. This study delivers the first autonomous-region-scale, systematic InSAR deformation dataset for Guangxi, providing a robust scientific foundation for spatial planning, infrastructure management, and disaster-risk mitigation.