Formation conditions and susceptibility assessment of karst collapses in the northern hilly area of Guangzhou City

Karst collapse is one of the main geological disasters in the northern hilly area of Guangzhou City, posing practical threats to public safety and affecting harmonious living conditions, thereby constraining local rural revitalization and development. This study analyzes the formation conditions of karst collapses in the northern hilly area of Guangzhou, including karst development degree, conditions of overlying soil layers, and hydrodynamic conditions of groundwater. Based on this analysis, six evaluation factors—karst development degree, soil layer thickness, soil layer structure, annual variation range of groundwater level, extent of fracture influence, and density of collapse points—are selected. The weight of each factor is determined by analytic hierarchy process (AHP), and a comprehensive index method is employed to establish the susceptibility assessment model for karst collapses in the northern hilly area of Guangzhou City. The results show that the areas of high, moderate, and low susceptibility to karst collapses in this region are 4.77, 14.24 , 21.71 km², respectively. Karst subsidence occurrences are predominantly distributed in high vulnerability areas (94.29%) and moderate vulnerability areas (5.71%), validating the rationality of vulnerability zoning assessment. The research findings provide a basis for geological disaster early warning and prevention zoning for local karst collapse, and also provide geological support for promoting rural revitalization and development.