Kan KOYAMA, Makoto FUJITA, Yuichi MAEDA, Yasuyuki TADA, Hirotaka OCHIAI, Tosiaki SAMMORI, Hiromu DAIMARU, Wataru MURAKAMI, Takayuki KAWAI and Naoki IWAMURA
Abstract
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.
Key wordsFlocal downpour, slope failure, tuff breccia, old crack, vegetation
type