Typhoon 0410 Causes Sediment Disaster in Tokushima Prefecture
Yoshifumi Satofuka and Takahisa Mizuyama
Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Oiwake-Cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
At the end of July 2004, Typhoon 0410 struck the Naka River basin in Tokushima Prefecture, triggering numerous slope failures, killing two residents, and largely or totally destroying many houses. We examine this sediment-related disaster and the phenomenon of landslide dam formation in which slope failure triggered by torrential rain blocks the river course. In Atsue, Kisawa Village, the landslide slope failure was 1,000 m long and 100 m wide. Such large slope failures may form landslide dams, greatly influencing the effluence of water and sediment in mountain basins. Using a numerical simulation model, we reproduced the process in which failed sediment forms a landslide dam and applied it to the case occurring as a result of Typhoon 0410.