Abstract
Gravitational slope deformation and its development process in the Kamikochi area, from the northeast of Tokugo Pass to Mt. Ohtaki, were examined by topographic interpretation using maps made from a 1-m-mesh airborne LiDAR DEM. Microlandforms of gravitational deformation origin occur ubiquitously on the NE-SW trending main divide and on the NW-facing slopes, whereas on the SE-facing slopes they are limited to branching ridges. Analyses of the gravitationally deformed units indicate that the movement started as small-scale deformation, was succeeded by integration that formed larger-scale units, followed by disintegration and localization of the deformation units. Few gravitational deformation units grew into landslide bodies with
clear sliding surfaces, and the deformed slopes are mostly in the sagging state. Gravitational deformations in the study area are now in the disintegration stage, comprising categorized rock failures without transitional stage of deep-seated slow landslides. The gravitational deformations in this area are inferred to have started forming before 12.4 ka when the Kamikochi Valley was dammed and filled up.
