Abstract
The considerable landslide occured in spring, 1971 when a hill was being cut and the surface of the road arrived nearly at the projected level. It seemed that the landslide was due to the unbalance of the shearing stress by the open cut of the road. For the prevention of the landslide a large amount of talus deposits should be removed which covers the hill. The subsurface structure was investigated by geological survey with the boring, refraction shooting and resistivity method. The talus deposit consists of two layers: the upper one has large boulders and the mud and the lower does gravels and the clay. Their total thickness is taken as 7 m on an average. The next layer is the tuff having the thickness of 10 m and the base rock is the conglomerate. Of course, every layer interferes each other and it is changed gradually to the other. Removement of talus deposits as well as treatment of the undergroud water in the tufaceous layer should be the present problem.
