磐梯山カルデラ壁下部の崖錐斜面上を流下する土石流の到達距離

概要

論文の詳細を見る
To examine (1) the factors affecting the running distance of debris flows, and (2) the role of the debris flows in the talus slope development, field investigation was carried out on talus cones located at the base of a caldera wall of Mt. Bandai in Fukushima Prefecture, Japan. The occurrence of debris flows was observed from May 1999 to November 2000. Dimensions of the cliff and talus slope and the running distance of the debris flow were measured through aerial photo interpretation and geometrical field survey. Results of the field observation lead to the following conclusions. (1) Debris flows are classified into two types: flows ceasing on the talus slope (type-A) and flows running out the talus slope (type-B). (2) Type-A debris flows occur when L_c/L_t < 0.7 and type-B debris flows occur when L_c/L_t > 0.7, where L_c is the horizontal length of cliff and L_t is the horizontal length of talus slope. (3) The value of H_t/(H_c + H_t) is higher at the slope with type-A debris flows and is lower at the slope with type-B debris flows, where H_c is the vertical length of cliff and H_t is the vertical length of talus slope. These findings suggest that type-A debris flows transport the talus materials downslope but do not hinder the development of talus slope, while type-B debris flows erode the talus materials and hinder the development of talus slope.
日本地形学連合の論文
2002-07-25