Shigemitsu SUGIHARA, Masahiro KAIBORI, Tetsuya KUBOTA, Yoshiaki KASHIWABARA and Kohei FURUKAWA
Abstract
The deluge on July ‚Q‚P ‚Q‚O‚O‚X in Hofu\Yamaguchi triggered tremendous damage and resulted in many causalities in the area. Geologically, the area consists of granite and has had many sediment\related disasters such as the one in August‚P‚X‚X‚RDAccording to an interview with local residents, such a serious disaster had not occurred for more than ‚Q‚O‚O years. Therefore, it will be very effective for planning disaster\prevention measures counting the regularity of sediment deposition, if we can obtain it accurately.
In this report, we considered the regularity of sediment deposition in Hofu\Yamaguchi, by using the result of carbon dating of carbonized wood gathered at Upper region of Gyokusen Pond and Ishihara region, as well as considering the situation of black soil layers including carbonized wood. Consequently, the sediment disaster as intense as the one on July ‚Q‚P ‚Q‚O‚O‚Xis estimated to occur once in every ‚P‚W‚T|‚R‚V‚O years in Upper region of Gyokusen Pond and once in every ‚P‚S‚T|‚Q‚Q‚O years in Ishihara region.
Key wordsFdebris disasters, carbon dating, regularity of sediment deposition