Debris Flow Disasters at the Harｉhara River, Izumi City, Kagoshima Prefecture, 1997

平成9年7月10日午前1時頃, 鹿児島県出水市針原地区で発生した土石流によって, 死者21名, 負傷者13名がでる災害となった。本研究では, 洪水流出解析を行って針原川の洪水流出特性を検討するとともに, 深層斜面崩壊を模擬して土石流を発生させた数値解析を行い, その氾濫・堆積過程の再現を試みる。さらに, この計算結果をもとに, 計画を上回るような土石流に対して今後どのように取り組めばよいかについて言及する。
A severe debris flow disaster occurred at the Harahara River, Izumu City, Kagoshima Prefecture, Japan at the midnight of June 10, 1997.Twenty‐one persons were killed and 18 houses were destroyed by the debris flow. The debris flow was caused by a big slope failure with sediment volume of 160, 000 cubic meters due to heavy rainfall.In this paper, a numerical simulation was performed to explain the behavior and the depositional processes of the debris flow.The actua phenomena such as a sediment depositional area. And a thickness of deposits are fairly well explained by the the calculation.