Risk Evaluation of Drifting Ship by Tsunami

Abstract

Drifting ship due to tsunami inundation flow may cause additional damage in harbor area. Many drifting ships were found in the 2011 Great East Japan earthquake tsunami and these caused various problems (damage of ships themselves, striking other structures and obstacle for restoration). In this sense, it is very important for disaster prevention to predict the drifting motion of a large ship by tsunami current. This study aims to simulate the drifting motion of ships by the 2011 Tohoku earthquake tsunami in Kesennuma harbor, Miyagi Prefecture. First, we simulated the hydrodynamic features of the 2011 tsunami by numerical simulation. Secondly, we analyzed the drifting motion of large ships using the result of tsunami numerical simulation. In the analysis, several test cases were conducted by changing parameter and initial position of the ship. Then we verified the results of the ship drifting simulation by comparing with actual grounding position of ships. Throughout the comparisons and verifications, we found the grounding position by the simulation was generally consistent with actual position of ships. Although it is necessary to verify the drifting route of ships, the results suggest that this model is beneficial for future disaster prevention.