Quantitative identification of landslide hazard in mountainous open-pit mining areas combined with ascending and descending orbit InSAR technology

Numerous open-pit mines are scattered within the southern mountainous areas of China. Due to the complex mountainous terrain and abundant rainfall, surface disturbances caused by open-pit mining activities pose a serious risk of landslides. To identify potential landslide hazards in mountainous open-pit mining areas in advance, this study proposes a quantitative method that utilizes ascending and descending orbit Interferometric Synthetic Aperture Radar (InSAR) technology to accurately identify landslide hazards. We select the Xiaolongtan coal mining area in Yunnan, China, as a case study. Small Baseline Subset InSAR (SBAS-InSAR) technology was employed to obtain the Line of Sight (LOS) deformation of ascending and descending orbits from November 2019 to November 2021. Following this, two-dimensional deformations were calculated based on the obtained LOS deformations. Multiple remote sensing data sources, including Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) and Landsat 8 Operational Land Imager (OLI), were utilized to extract potential landslide points based on vertical deformation. A combined subjective and objective weighting method was then used to assess the landslide hazard in the study area, and an information quantity model was constructed for landslide hazards in the mining area. Finally, based on high-resolution remote sensing images from the study period, potential landslide hazards were identified in the study area. The results reveal that the vertical deformation rate in the mining area ranges from − 231.73 to 81.42 mm/year, indicating significant subsidence and uplift tendencies. A total of 2353 potential landslide points were identified, primarily located near the slopes of two open-pit mines and in areas with low vegetation coverage. The Xiaolongtan and Buzhaoba open-pit mines, along with the surrounding regions in the study area, were identified to exhibit relatively high landslide hazards. Among the three coal mine waste dumps, the Beipingba waste dump presents a higher landslide hazard. This study provides a scientific basis and practical reference for identifying landslide hazards in mountainous open-pit mining areas.