Geological and Geomorphological Factors at some Landslide Areas in Shikoku

Abstract

From a geological and geomorphological point of view, the writer described some landslide areas, and pointed out their characters. The one is an active landslide movement of high velocity and caused by a certain character of bedrocks and geological structures. This kind often causes a great deal of damage. The other occurs at areas with the Quartarnary detrital deposits and exhibits a continuous landslide movement, which is not so violent as to cause damage to people and houses. The landslide activity of the latter mainly occurs in a buried topographical surface under debris and the depositional stucture of them. Seismic prospecting does not show so great a deference in seismic wave velocity between the deposits and the bedrock.