Studies on development of slope disaster risk map evaluating the generation and transfer process of volcaniclastic materials based on the perspectives of eruption history

In recent years, enormous slope disasters have frequently occurred in volcanic areas. In 2013 the Izu Oshima heavy rain disaster was occurred, and in 1990, 2001 and 2012, numerous slope disasters due to rainfall were repeatedly occurred at Aso area in Kumamoto. The 2016 Kumamoto Earthquake and the 2018 Hokkaido Eastern Iburi Earthquake caused a lot of landslides in volcanic areas. The main cause of these slope disasters is the shallow landslides of unstable volcaniclastic materials on slopes. One of the initial research porposes was to answer the basic questions such as why the slope failure occurs on the slope of volcaniclastic materials and where it tends to occur. This research was able to answer these questions to some extent.