[S04-P] Poster

[S04-P-06] The large Hyuga-nada earthquake on June 30th, 1498 is a fake earthquake −Examination of the damage descriptions in Kyushu in the war chronicle "Kyusyu-gunki"−

^○Tomoya Harada, Akihito Nishiyama, Kenji Satake, Takashi Furumura (Earthquake Research Institute, The University of Tokyo, Tokyo, Japan)

A large earthquake in Hyuga-nada Sea on the east side of Kyushu Island, Japan along Nankai Trough in "Mi-no-koku" (9-11 a.m.) on June 30th, 1498 on Julian calender, which was based on the descriptions about serious damage due to a large earthquake in Kyushu in the war chronicle "Kyushu-gunki", has been accepted by many seismologists as the 1498 Meio Hyuga-nada earthquake. "Kyushu-gunki" is one of the popular novels which was written more than 100 years after the 1498 event. The damage descriptions have been used to estimate the location of this earthquake without evaluating the reliability. In this study, in order to assess credibility of the description, we carefully examined writing process of "Kyushu-gunki" and damage descriptions in this war chronicle. Our findings are summarized as follows: (1) "Kyushu-gunki" was completed in Kyushu in 1607, hence the writers' experience of the contemporary 1596 destructive earthquake in Kyushu might have influenced the description of the damage of 1498 earthquake; (2) Damage descriptions of "Kyushu-gunki" were generic without location information and most of them are cited from descriptions of damage in Kyoto due to the 1185 large earthquake in the war chronicle "Gempei-josui-ki"; (3) Origin time ("Mi-no-koku") of this event is described only in "Kyushu-gunki" and it is close to that of the 1498 great Tokai earthquake ("Tatsu-no-koku": 7-9 a.m.); (4) The chapter of the earthquake damage also includes serious famine in Kyushu in 1503 and pains of people by many disasters, making this chapter a stage setting for later stories. To make a story of the war chronicle more interesting, writers seem to have created fictitious story of serious damage due to a large earthquake in Kyushu based on old war chronicles and some records of the 1498 Tokai earthquake. Therefore, it can be concluded that the 1498 Meio Hyuga-naga earthquake is a fake earthquake and it should be deleted from Japanese historical earthquake catalog.