Volume 78 (2005) Issue 12 Pages 859-866
To examine running distance of debris flows occurring on the talus slopes, rainfall experiments were carried out. The quantity Vt is defined as the reciprocal of the threshold value of Lc/ Lt, at which debris flows just reach the bottom of the talus slope, where Lc is the horizontal length of the cliff and Lt is the horizontal length of the talus slope. The value of Vt is also a measure of the possibility of sedimentary outflow from the talus slope by debris flow. The value of Vt shows strong correlation with the hydraulic conductivity of talus sediment (K) and the rainfall intensity (Ir). The outflow of debris from the talus slope can be predicted using the values of Lc, Lt, K, and Ir.