Multi-hazard risk mapping for coupling of natural and technological hazards

Technological hazards induced by natural hazards have a significant impact on human life and economy. Their power exceeds the impact of the natural hazards that caused them. However, most of the multi-hazard risk maps failed to incorporate technological hazards when mapping multi hazard risk. To address this problem, we established a hybrid multi-hazard risk assessment methodology that calculates the risk caused by natural and technological hazards in a three-step process. First, the possible natural and technological hazards in a given region are identified by hazard-forming environment analysis and hazard source investigation respectively. A scenario simulation is adopted to analyze the intensity and impact scope of these hazards. Second, the triggered relationships among natural and technological hazards are analyzed by a hazard matrix. Then, the radar graph is adopted to calculate the multi-hazard intensity under the coupling effect of all possible hazards in this region. Third, the multi-hazard risk is calculated by aggregating land use data and multi-hazard intensity together. This methodology was applied in Huairou Science City (HSC), Beijing. The result shows that the joint action of earthquake and liquid ammonia leakage is the main reason for the high risk in the central area of HSC. The methodology developed in this study can clearly show the different impacts of each hazard on a given region under the action of hazard coupling, and the calculated results can better reflect the actual disaster situation.