[M-IS15] Geophysical particulate gravity current

[MIS15-01] Initiation and runout characteristics of debris flows in Ohya landslide and Mt. Fuji

★Invited Papers

*Fumitoshi Imaizumi¹, Shoki Takayama¹, Atsushi Ikeda² (1.Faculty of Agriculture, Shizuoka University, 2.Faculty of Life and Environmental Sciences, University of Tsukuba)

Keywords:debris flow, field monitoring, UAV

Debris flows are sediment transfer processes that can cause severe damages to property and life, due to their high velocity, large volume, and destructive power. Many of previous studies have been conducted in the lower channel sections of debris flow torrents, while debris flows in their initiation zones have been poorly understood because of difficulty in field monitoring. In recent years, LiDAR and UAV techniques have been greatly developed, contributing accumulation of data in the initiation zone. Developments of monitoring devices also enable us to obtain various types of data on the debris flow characteristics. We have conducted field monitoring of debris flow in Ohya landslide and Osawa failure in Shizuoka prefecture, central Japan, using. Monitoring results in Ohya landslide showed that many debris flows initiated in the channel sections with thick channel deposits and the sections near junctions with tributaries. Flow characteristics were different among debris flow events and surges. In Osawa failure, ground-freezing highly affected initiation and runout characteristics of debris flows.