Building damages due to mud flow on Izu Ohshima, Japan in October, 2013

Yasuo Nihei, Hiroyuki Nagano, Kazuaki Otsuki, Wataru Yakita, Jyunya Kaji

Tuesday 30 june 2015

17:57 - 18:00h at Mississippi (level 1)

Themes: (T) Sediment management and morphodynamics, (ST) Sediment transport mechanisms and modelling, Poster pitches

Parallel session: Poster pitches: 7A. Sediment - Erosion

In Oct., 2013, typhoon no.1326 brought heavy rain, which exceeded totally 800mm and showed 120mm per hour, in Izu Ohshima Then huge sediment disaster has occured in Motomachi area, located at west part of Izu Ohshima. In this study, we clarfiy building damages due to sediment disaster. For this, we conducted field survey for bulding damage and inundation depth in the above area and also performed numerical simulation of mud flow to examine the fluid force on buildings. The results indicated that building damages in mountain and sea sides of the above area were caused by the fluid force of mud flow and channel clogging due to sediment and driftwood, respectively. The range of building damages in the sea-side area was limited 40- 60m from the Ookanazawa channel in the lateral direction. Such a narrow range of the dameges corresponds to specific characteristics of sediment disaster. This shows a useful evacuation system for sediment disaster.