*4.2. Debris Flow Area (Area II)*

The debris flow area presented a long and narrow shape, and bedrock appeared in the upper part of the debris flow area. The bedrock surface had signs of scratch, and there was an exposed water head. There was also a water head on the western side of the sliding source area. This might suggest that there was sufficient groundwater in the area that promoted the sliding of the landslide. In this area, the volume of the sliding body increased due to the entrainment. The area was 6.8 <sup>×</sup> 103 m2, the average thickness of the sliding body was 3–6 m, and the volume was about 25.0 <sup>×</sup> 104 m3.
