In the early morning of Dec. 31, 1703 (Genroku 16), an enormous earthquake with magnitude of 8.2 occurred in the south sea region of the Kanto District. It is well known that after the occurrence of the earthquake a huge tsunmi was generated, and that the coasts of the Boso Peninsula, the north coasts of Sagami Bay, and the east coasts of the Izu Peninsula were seriously damaged.
Recently several old documents of the Genroku tsunami were also discovered on the coasts of the Tokai district, the Kii peninsula, and the Shikoku Island. In two towns, Nishina and Toi, on the west coast of the Izu Peninsula, inundation height was estimated 3 meters, and the residential areas of these towns were slightly submerged. At Miho village in Shimizu city on the west coast of Suruga Bay, residential areas were intermittently submerged for more than ten days, and the people took refuge in higher places. On the mouth district of the Lake Hamana, seaside banks were eroded, and the mouth of the lake became broader. Thirty-three large junks out of 36 anchored at the open sea of Arai town near the lake, were wrecked. In Ono town on the Chita Peninsula inside the Bay of Ise, a garden of Naiku shrine was washed and eroded, where inundation height was about 2 meters. Tsunami was also noticed at the port of Nagoya. Miwasaki and Taiji towns and Haida village on the south east coast of the Kii peninsula were seriously damaged in spite of the long distance from the tsunami origin. In these places 46 houses were washed away in total and the observed tsunami climbed up to 3 or 5 meters. Tidal irregulaity was also noticed in several ports of Kochi Prefecture on the Shikoku Island.