歴史地震の研究 (3) : 明応 7 年 8 月 25 日(1498 年 9 月 20 日)の地震及び津波災害について

Abstract

The earthquake and tsunami damages caused by the Meio earthquake of 1498 are investigated from old documents collected to understand the damage locality and the occurrence characteristics of an earthquake in off Tokaido districts. The distribution of seismic intensity and tsunami inundation heights are also studied. About 500 kilometers along the Paciffic Coasts in Tokaido districts, Central Japan were hit by the tsunami of this earthquake. Most severe inundation heights in the range of 8 to 15 meters are estimated at the Shima Peninsula. Wave source is estimated to be located along the Nankai trough, extending up to the south of lzu Peninsula. The remarkable changes in topographical features were the appearance of the sinking of several large areas such as Hamana, Yaezu, and Tsu distridts and of the opening of the Hamana lake to the sea. It is estimated that about 8,500 houses were destroyed and about 51,000 peoples were drowned by the 1498 earthquake and tsunami. The magnitude of this earthquake is estimated at 8.3 and the epicenter at 138.1°E and 34.0°E.