Host: Japan Society of Hydrology and Water Resources
Name : Proceedings of 2024 Annual Conference, Japan Society of Hydrology and Water Resources
Date : September 10, 2024 - September 12, 2024
The current landslide warning technology uses a uniform rainfall index for the entire country and does not take into account differences in geology, topography, land use, etc. On the other hand, there are a vast number of landslide hazard areas in Japan, and it is unrealistic to define an optimal rainfall index for each of them. Therefore, Kosugi (2015) proposed a method to evaluate landslide hazard from various perspectives by drawing many snake curve diagrams with various combinations of indices. In addition, Kosugi (2015) proposed to set CL as the line connecting the maximum value in each of the snake curve plots. The basis for the occurrence of disasters in this method is "unprecedented heavy rainfall," and it is expected to be a method that accurately captures the characteristics of landslide disasters.
Moreover, Kosugi (2022) proposed an improved version of this method. That is, Kosugi (2022) proposed to use the point in the past when "the current rainfall does not exceed the historical maximum" as an index to evaluate the risk of landslide occurrence (i.e., unprecedented rainfall index). In this study, the usefulness of the unprecedented rainfall index is discussed based on the analysis of actual cases of landslide disasters.
