抄録
Local downpour caused two hundred eighteen collapses in the hilly foot area of Mt. Daisen in Kotoura town, Tottori Prefecture on September 4, 2007. The collapses are dominant on the clearcut areas and the young stands of Chamaecyparis obtusa. The alternation strata of tuff breccia, which dominate hydrological and soil mechanical characteristics, affected the locations and the size of the collapses. The existence of an old crack is enumerated as a cause of the collapse of convex geographical features.
