Currently, the concept of "multi-hazard" is gradually derived from the research fields of disaster chain, domino effect, and Na-tech . In the United Nations' Agenda 21 for sustainable development , the term "multi-hazard" was first raised to calls for "complete multi-hazard research" as a part of human settlement planning and management in hazard-prone areas. Since then, the issue of multi-hazard is coming under increasing attention in scientific research and is of great concern for governments .