EFFECT OF SEDIMENT TRANSPORT ON TSUNAMI HAZARD AND BUILDING DAMAGE – AN INTEGRATED SIMULATION OF TSUNAMI INUDATION, SEDIMENT TRANSPORT AND DRIFTING VESSELS IN KESENNUMA CITY, MIYAGI PREFECTURE DURING THE GREAT EAST JAPAN EARTHQUAKE –

Abstract

 An integrated tsunami model consisting of models for simulating tsunami inundation, drifting objects and sediment transport, was newly developed to evaluate the effects of these multiple phenomena. A scenario of complex tsunami damage enlargement in a bay with bottleneck was revealed. The tsunami hazards in Kesennuma City, especially at the inner part of the bay such as Shishiori area, were enlarged by erosion in the bottleneck of the bay. The bathymetric change increased the drift distance of the drifting vessels. In addition, through the tsunami fragility functions based on dataset of actual damaged building and numerical results, it was evaluated that the 200 - 1,800 wooden buildings were washed away owing to sediment transport. Furthermore, it is found that the estimation accuracy of damage scale by the conventional fragility functions was suitable, although the estimated building damage near the sea and inland was under and overestimated, respectively.