After the eruption of Mt. Fuji in 1707, tremendous volumes of sediment flooded the right bank of the Sakawa River in the Ashigara Plains, and other areas. We conducted field studies of the right bank of the Sakawa River and other areas in order to determine the terrain formed by the scoria]flood flow flooding and the distribution, stratum thickness, properties, and other features of the sediment deposits. At the same time, we also determined the terrain before the Hoei eruption. In the upstream region, the scoria]flood flow flooding created the Madarame]Kanaishima Uphill, while in the midstream region, the grooved concave ground was formed by erosion. The scoria]flood flow covered an area of about 12.4 km2, approximately 61% of the total area of the right bank. The maximum thickness of the flood deposits was 4 to 4.5 m. The total volume of soil deposited on the right bank and other areas was approximately 1.8 x 107 m3.

Key wordsFAshigara Plains, Sakawa River, Mt. Fuji Hoei Eruption, scoria]flood flow, Okuchi Bank