Abstract
This research aims to elucidate the navigational situation of ships during the massive tsunami that occurred in the Tohoku district of Japan on 11 March, 2011. In particular, it focuses on the time the massive tsunami encountered ships. AIS, which is required to be fitted aboard large ships for identifying and locating vessels, was used for the analysis of the navigational status of ships. It was confirmed that a group of ships sailing off the coast suddenly changed course. It was also verified that the ships had been struck by the tsunami, and the time of the strike was identified. The novelty and importance of this research are as follows. First, the behaviour of many ships that encountered the massive tsunami was clarified. There are no earlier instances of simultaneous and detailed recording of the behaviour of many ships encountering a massive tsunami. Second, the movement of the ships that encountered the tsunami was analysed, and the time of the maximum wave of the tsunami was verified. The research presents, for the first time in ship history, the status of a ship at the time of a tsunami using objective navigational data.
