土石流数値シミュレーションの一次 元計算領域と二次元計算領域の設定 方法の検討-GISと連携したHyper KANAKO システムを活用して一

摘要

Debris flow numerical simulation is effective for hazard mapping and disaster prevention. One-dimensional (1D) simulations are usually applied in steep upstream areas, whereas two-dimensional (2D) simulations are often applied in low-slope downstream areas. We applied debris flow simulation on two torrents, one in the Ibi area of Gifu Prefecture, where a large-scale sediment disaster had occurred in 1895, and one in Izu Oshima, where a large debris flow occurred in 2013. We used the usual method, setting a 1D area for the steep torrent, and a new method, setting a 2D area from the upstream steep area. We used the Hyper KANAKO, a GIS-equipped debris flow simulation system. The new method described the torrents well, especially for the Izu Oshima disaster, where an undulating surface exists from the steep area and large scale debris flow occurs.