[H-GM04] Geomorphology

[HGM04-10] Impact of the Sekimi pyroclastic flow on the landform development of the Kinoe River basin on the northern foot of Mt. Daisen volcano

★Invited Papers

*Yoshinori Kodama¹, Aoi Ogawa² (1.Faculty of Agriculture, 2.Graduate student, Faculty of Agriculture, Tottori Univ.)

Keywords:the Sekimi phyroclustic flow, Sandy pyroclastic flow, The effect of particle size mixing on sediment transport, fluvial terrace formation processes, Northern foot of Mt.Daisen volcano, the Kinoe river basin

A terrace surface classification was carried out in the middle reach of the Kinoe River. It was revealed that the Daisen-chou Tanaka surface and the Iwaigaki surface were not formed in conjunction with the Nawa pyroclastic flow but were formed by active sediment movement associated with the Sekimi pyroclastic flow. As a result of the accumulation of a thick layer of fine-grained sandy Sekimi pyroclastic flow deposits in the upper reaches of the valley, the grain size mixing effect on sediment transport caused the riverbed gravel of the Kinoe to move actively, widening the valley floor and leaving terraces.