愛知県小原村周辺の山崩れについて (I) -斜面形,土層構造と山崩れについて-

Abstract

Morphology and subsurface structure of slopes are investigated in Nishimikawa Mountainswhere small scale landslides occurred densely on granitic slopes in 1972. Geomorphologicalanalysis using air-photograms and 1/25000 and 1/2000 topographical maps reveals that wherelandslides occurred most densely, valley walls are V-shaped consisting of several segments, andthat where landslides were rare, valleys are U-shaped and the valley slopes are convex decreasingtheir declivity continuously upslope. It is suggested that difference in petrography tends to makedifference in prevailing wasting agents on the mountain slopes under the same external conditions.Detailed investigation of subsurface structure of the slopes in a small drainage basin involving manylandslides gives the informations about the critical depth of loose horizon for the occurrence of theslide. Thus, a quantitative examination of production, transport, and removal by landslide ofloose material yields a general scheme of slope denudation accounting for creep, surface erosionand landslides.