A huge landslide was generated at the up stream side of the Aratosawa Dam during the earthquake.It was about 1.3 km in total length, about 900 min maximum width and the distance of the main slide was about 320 m.The amount of movement mass totaled approximately 67 million m3 and the land slide scarp was 148 min height. Fig. 11 shows the out line of the land slide and an aerial photograph.It can be seen that the middle part of the landslide moved as a rigid body and stopped once it hit the mountain on the southeast side. The road has been left on the sliding mass as it was.