Abstract
The area where the landslides occurred is situated to the west of Atsushio in the Higashiaizu area, Fukushima prefecture. Geologically the area is occupied mainly by Neogene sediments and Quaternary deposits.
The landslides in this area can be divided into three types, on the basis of geoglogic features, as follows:
1) Landeslides along the line of the fault zone.
2) Block glides down the bedding plane.
3) Rock fragment flows.
Among them, the Block glide type causes the greatest disaster.
The mechanism of the Block glide was pursued in our studies, and in our efforts to determine it the author carried out the stability calculation of the landslides and the detailed geological survey. And it was concluded that Block glides are due to the permeation of water into vertical crucks, which are controlled by the geologic structure and are caused to occur at intervals of 1.5 meters.
