Three-dimensional surface deformation field monitoring and influencing factors analysis in mountainous areas based on SBAS-INSAR technology (Tianjin, China)

Synthetic aperture radar interferometry (InSAR) technology has emerged as a critical methodology for disaster reduction and prevention, offering unprecedented all-weather operational capabilities and extensive spatial coverage that effectively address the limitations of traditional detection methods. Despite the inherent challenges of temporal and spatial coherence in conventional time-series InSAR approaches, the small baseline subset InSAR (SBAS-InSAR) technique presents a sophisticated solution by significantly mitigating coherence-related uncertainties and enhancing measurement precision. While existing research predominantly focuses on urban environments, this study uniquely addresses the research gap in mountainous terrain deformation monitoring by utilizing Sentinel-1A and 1B single-look complex (SLC) data from ascending and descending orbits between January 2018 and May 2022. The comprehensive analysis of land subsidence in northern Tianjin's mountainous region revealed multi-directional surface deformation characteristics, with validation against GNSS Kriging interpolation data demonstrating root mean square errors of 5.74 mm and 5.09 mm in vertical and east-west directions, respectively. The investigation exposed predominantly horizontal deformation influenced by large-scale engineering activities, topographic conditions, and precipitation patterns, with notable findings including a maximum north-south deformation of 54.62 mm in the Maojiayu landslide area and vertical cumulative deformations of 21.10 mm and - 10.31 mm in Maojiayu and Taoosi landslide areas. These results substantiate the efficacy of InSAR technology in monitoring surface deformation in mountainous regions, offering critical insights for regional geological disaster prevention and mitigation strategies.