Analytic hierarchy process combined with ArcGIS to assess the landslide susceptibility of the lower flow of the Ryesong River region, Democratic People’s Republic of Korea

This study aims to delineate landslide susceptibility maps via the analytical hierarchy process (AHP) method in the lower flow zone of the Ryesong River region, Democratic Peoples’ Republic of Korea (DPRK). The study area is typically prone to high susceptibility to landslides due to geological conditions, including faults, heavily weathered lithology, and relatively high annual precipitation. Nine conditioning factors, including slope, elevation, land use, lithology, distances from faults and rivers, rainfall, curvature and aspect derived from remote sensing data, geological maps and meteorological records, were considered. These variables were standardized and analyzed via the analytical hierarchy process (AHP), which generates relative weights through pairwise comparisons. This study identifies the dominant factors controlling landslide susceptibility in the region. Slope (39.48%) and elevation (21.78%) emerged as the most critical predisposing factors, whereas land use (16.03%) and lithology (9.29%) were significant secondary contributors. This hierarchy quantitatively confirms the compound risk from topographic, anthropogenic, and geological factors. Spatially, areas of high and very high susceptibility, constituting 34.8% of the study area, are concentrated on steep (15–35°), fault-proximal slopes with weathered sedimentary lithology and thin forest and grass land covers. The resulting landslide susceptibility map (LSM) was validated via a receiver operating characteristic (ROC) curve, which yielded an area under the curve (AUC) value of 0.8286, indicating good predictive performance. The LSM offers a valuable tool for spatial planning, early warning systems, and risk mitigation strategies, particularly in the face of increasing climatic extremes that intensify landslide triggers. This integrative approach not only enhances geological hazard management in mountainous terrains but also provides a replicable framework for similar environments globally, contributing to the broader goal of sustainable land use and disaster resilience.