Anatomy of cascading natural disasters in Japan: main modes and linkages

In order to contribute to the development of risk assessment, cascading natural disasters which are sequences of natural hazards was studied, and the patterns of the interactions between natural disasters were investigated. The data were collected from the database of Japanese newspaper. The relationships between each natural hazard were emerged and divided into four modes: striking, undermining, compounding, and blocking modes. Striking mode means a primary disaster provides sufficient energy to move a significant mass or to propagate the energy through media. In undermining mode, a primary disaster lowers the resistance or weakens a system maintaining mass and causes to collapse. Compounding mode of the linkage shows that a primary disaster reduces the strength of a system. Its difference from undermining mode is that this mode adds to the amount of mass affected. Blocking mode is found in an event blocking steady flows. The results are important for understanding of the impact of these types of cascading natural disaster and so are valuable as a basis for the identification, description, and development of countermeasures.