2013/08/23 by Masataka Ando, Mamoru Nakamura · 1 voice
Earth and Planetary Sciences · Computer Science · #earthquake and tectonic studies #Geological and Geochemical Analysis #Seismology and Earthquake Studies
paper · pdf · doi:10.1093/gji/ggt270
openalex publication_date 2013/08/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/23
Historical documents reveal that a series of large earthquakes occurred in the past 1400 yr along the Nankai Trough at an interval of 100–150 yr. These documents, combined with recent seismological data, show that the five most recent large earthquakes are megathrust events that occurred on the upper interface of the Philippine Sea Plate. However, the 1605 Keicho earthquake (Mt = 8.2) differs from these five events: extensive tsunami damage occurred along the western coast of Japan, despite a relative lack of damage due to strong ground motions. Based on these data, the earthquake is thought to be a ‘tsunami earthquake’, which generates a disproportionally large tsunami compared to its seismic waves. In this study, we carefully examined a diary in which the writer described earthquakes felt in Kyoto over 41 yr. Detailed analysis shows that it is extremely unlikely that the writer did not record the event in the diary. Assuming that this event occurred on the shallower plate interface near the trench axis, a tsunami simulation was performed based on the data recorded in historical documents. If the 1605 earthquake is a ‘tsunami earthquake’, this earthquake cannot be considered an ordinary thrusting event on the seismogenic zone of the plate interface that occurs at an interval of 100–150 yr along the Nankai Trough. If we exclude this event from such a group, the interseismic interval increases to approximately 200–400 yr, which implies that large earthquakes occur with a wide range of interval.