Abstract
Recently, landslides triggered by heavy rain have occurred widely. This study note was designed to have a good grasp of the relationship between a heavy rain and ground water level in a shear zone landslide area. As a base of the method of prediction of safety factor of slope based on rainfall, the amount of precipitation of agricultural landslide areas and ground water level in a lot of bore holes set in the areas were observed, and the relationship between them were analyzed. As a result, it became enabled to grasp approximately the relationship between them in the area, by determining the half-period of accurate rain based on the change of ground water level cased by rainfall. In addition, from the view point of the relationship of the accurate rain and ground water level, it is considered that there are two kinds of modes there, and that the difference of forms of rainfall causes them to appear.
