HR: 09:30h
AN: S21C-07    [Abstracts]
TI: Synchronous seismicity-rate-changes from the predicted rates by the ETAS model in and around the northern Japan preceding the 2003 Tokachi-oki earthquake of M8.0
AU: * Ogata, Y
EM: ogata@ism.ac.jp
AF: Institute of Statistical mathematics, Minami-Azabu 4-6-7, Minato-Ku, Tokyo, 106-8569
AB: The epidemic type aftershock sequence (ETAS) model predicts the normal seismicity-rates that superposes the modified Omori functions for aftershock activities. Deviations (lowering and enhancement) of the seismic activities from the predicted rates by the ETAS model are revealed to have concurrently occurred during 1996 in four seismic regions, northern Japan. The respective deviations are explained by the changes in Coulomb failure stresses, caused by the same aseismic slip that is assumed to have occurred on a plate interface of the 2003 Tokachi-oki rupture of M8.0. The slip is also supported by a significant change in the distribution of fault mechanisms of moderate earthquakes in northern Japan, before and after 1996. According to the occurrence data of strong earthquakes of M5.0 or larger for the long period 1926-2003, the quiescence relative to the ETAS lasts about 10 years_f periods not only preceding the recent 2003 earthquake but also preceding the 1952 and 1968 great Tokachi-oki earthquakes.
UR: http://www.ism.ac.jp/~ogata/
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2004 AGU Fall Meeting