Hazard regionalization of debris-flow disasters along highways in China

Regional differences in China’s natural landscape involve significant differences in the distributions of debris-flow disasters along highways (DFDHs), which makes it very difficult to forecast, identify, and provide early warnings for such disasters. Previous research mainly focused on single-gully debris-flow disasters or a number of debris-flow disasters with similar morphological characteristics, which could not reflect the inherent mechanisms leading to the occurrence of DFDHs. Hazard regionalization of DFDHs in China can clarify the priorities and protection standards for different areas in China, and provide a theoretical basis for macro-policy formulation. We identify the hazard sources of DFDHs, extract hazard assessment indicators, and calculate the weight of each indicator using a cloud model-improved analytic hierarchy process. We draw basic maps of assessment indicators and perform a spatial analysis of hazard of DFDHs using ArcGIS, and a hazard regionalization scheme for DFDHs in China is developed. The results show that the degree of hazard of DFDHs in China ranges from 1.000 to 7.900. China is divided into low, moderate, severe, and extremely severe hazard areas. The extremely severe hazard areas are the Loess Plateau (north part of the QinBa Mountain area), the Taiwan–Wuyi Mountain area, the Sichuan–Yunnan Mountain area, and the Tianshan–Kunlun Mountain area.