Abstract
In Oct., 2013, typhoon no.1326 brought heavy rain, which exceeded totally 800 mm and showed 120 mm 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 the 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 drift wood, respectively. The range of building damages in the sea-side area was limited 40- 60m from the Ookanazawa channel in the lateral direction.
