HR: 08:40h
AN: S21B-03    [PDF]
TI: Real Time Earthquake Information System in Japan
AU: * Doi, K
EM: keijidoi@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 1130032 Japan
AU: Kato, T
EM: tkato@met.kishou.go.jp
AF: Seismological and Volcanological Department, Japan Meteorological Agency, 1-3-4 Otemachi, Chiyoda, Tokyo, 1008122 Japan
AB: An early earthquake notification system in Japan had been developed by the Japan Meteorological Agency (JMA) as a governmental organization responsible for issuing earthquake information and tsunami forecasts. The system was primarily developed for prompt provision of a tsunami forecast to the public with locating an earthquake and estimating its magnitude as quickly as possible. Years after, a system for a prompt provision of seismic intensity information as indices of degrees of disasters caused by strong ground motion was also developed so that concerned governmental organizations can decide whether it was necessary for them to launch emergency response or not. At present, JMA issues the following kinds of information successively when a large earthquake occurs. 1) Prompt report of occurrence of a large earthquake and major seismic intensities caused by the earthquake in about two minutes after the earthquake occurrence. 2) Tsunami forecast in around three minutes. 3) Information on expected arrival times and maximum heights of tsunami waves in around five minutes. 4) Information on a hypocenter and a magnitude of the earthquake, the seismic intensity at each observation station, the times of high tides in addition to the expected tsunami arrival times in 5-7 minutes. To issue information above, JMA has established; - An advanced nationwide seismic network with about 180 stations for seismic wave observation and about 3,400 stations for instrumental seismic intensity observation including about 2,800 seismic intensity stations maintained by local governments, - Data telemetry networks via landlines and partly via a satellite communication link, - Real-time data processing techniques, for example, the automatic calculation of earthquake location and magnitude, the database driven method for quantitative tsunami estimation, and - Dissemination networks, via computer-to-computer communications and facsimile through dedicated telephone lines. JMA operationally monitors earthquake data and analyzes earthquake activities and tsunami occurrence round-the-clock on a real-time basis. In addition to the above, JMA has been developing a system of Nowcast Earthquake Information which can provide its users with occurrence of an earthquake prior to arrival of strong ground motion for a decade. Earthquake Research Institute, the University of Tokyo, is preparing a demonstrative experiment in collaboration with JMA, for a better utilization of Nowcast Earthquake Information to apply actual measures to reduce earthquake disasters caused by strong ground motion.
DE: 7223 Seismic hazard assessment and prediction
SC: Seismology [S]
MN: 2003 Fall Meeting