Pumice-flow, its Landform and Its Erosion Processes

Abstract

The authere investigated the erosion processes of pumice flow deposits in the upper reach of the Goto River. The results are as follows: The first pumice now deposit was very highly absorptive of the moisture, and when it had a little moisture, there occurred columnar exfoliation of scarps. The development of hollow topography took place after the deposition of the loam and humus, induced from a landslide after the heavy rain fall and the eqrthquake etc. Also, the developments of the vertical gully type are enlarged by the underground water rather than the fluvial erosion.
The main factors for columnar exfoliation of scarps are 1) underground water, 2) fluvial water, 3) earthquake, 4) aridity, and 5) rain water. The main factors for columnar exfoliation of scarps are 1) underground water, 2) fluvial water, 3) earthquake, 4) aridity, and 5) rain water.