Reconstruction of the 1707 Hoei, Japan, tsunami that reached the southern coast of the Korean Peninsula

The 11 March 2011 Tohoku, Japan, tsunami reached the coast of Jeju Island, the southernmost Korean Peninsula, after about five hours from the origin time of the earthquake. The island is located in the backside of the epicentral Pacific region, and the direct propagation path is blocked by the Japanese Islands Arc. It implies that the tsunami observed in the Jeju Island is diffracted waves. The wave height observed in the island reaches about 0.2 m. There is no report of damage caused by the tsunami. On the other hand, there is a historical document which records an observation of earthquake and tidal waves simultaneously in the island. The date corresponds to the occurrence of the great 1707 Hoei earthquake (M~9) and tsunami in the Nankai and Tonankai areas, the offshore southern Honshu, Japan. The propagation path to the island of the Hoei tsunami is similar to that of the Tohoku tsunami, but is much shorter than it. In this study, we try to show that the 1707 historical observations in the Jeju Island was resulted from the great Hoei earthquake and tsunami in Japan, and how the maximum wave height was. Numerical simulations and investigations of historical documents are performed in parallel for this purpose. We assume that the source information of the 2011 Tohoku earthquake would be comparable to the 1707 Hoei earthquake because of the similar magnitude and tectonic environment. Therefore numerical simulations employ a variety of fault rupture models which are determined for the 2011 Tohoku earthquake. This study may extend to the prediction of any future tsunami in the island due to the potential megathrust earthquake which is expected to be co-located with the 1707 Hoei earthquake.