Provision of Earthquake Early Warning to the General Public and Necessary Preparatory Process in Japan

HR: 08:00h
AN: S21D-01 [Abstracts]
TI: Provision of Earthquake Early Warning to the General Public and Necessary Preparatory Process in Japan
AU: Tsukada, S
EM: tsukada@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: * Kamigaichi, O
EM: okamigai@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Saito, M
EM: msaito@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Takeda, K
EM: k-takeda@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Shimoyama, T
EM: shimoyama@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Nakamura, K
EM: kouji_nakamura@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Kiyomoto, M
EM: mkiyomoto@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AU: Watanabe, Y
EM: watanabe.y@met.kishou.go.jp
AF: Japan Meteorological Agency, 1-3-4, Otemachi, Chiyoda-ku, Tokyo, JAPAN, Tokyo, 100- 8122, Japan
AB: Earthquake early warning of JMA is to enable advance countermeasures to the strong motion disaster by providing expected seismic intensity and arrival time of the strong motion, as well as estimated hypocenter parameters, before the S wave arrival. However, due to its very short available time period, it is essential to well publicize the principle and technical limit of EEW, and proper actions to be taken when it is seen or heard, to utilize EEW effectively without causing unnecessary confusion. Accordingly, JMA decided to provide EEW in two steps. Namely, JMA started to provide EEW to a limited number of users who understand the technical limit of EEW and can utilize it effectively, such as for automatic control from August 2006. At that moment, EEW was not well known to the general public, so JMA started to provide it to the general public in October 2007, after publicizing the principle and proper actions to be taken. EEWs are issued basically several times for one earthquake improving the accuracy as available data increases as time passes, securing the promptness of the first issuance at the same time. On line connected computer can utilize such multiply issued information for automatic control. But, when they are transmitted to a public, it is impossible to respond properly, and also it is impossible to transmit all by characters and voice. So, JMA considered the issuance criterion and contents of EEW when it is issued to the general public to meet the following conditions. 1) Should be issued on the best timing, to avoid the false alarm, to secure the promptness as much as possible, and to make the revised issuance as few as possible. 2) Should be issued when really a strong motion is expected, and it should be made clear where the safety actions should be taken. As a result, - Issuance criterion : when the maximum seismic intensity 5 lower(JMA scale) or over is expected by using seismic records from more than one station. - EEW contents : Origin time, epicentral region name, and names of areas(unit is about 1/3 to 1/4 of one prefecture) where seismic intensity 4 or over is expected. Expected arrival time is not included because it differs substantially even in one unit area. Considering the gravity of EEW which can save lives, JMA is considering the framework to clearly define the responsibility of JMA, and to assure the technical standard of EEWs that will be issued from private companies to provide expected seismic intensity and arrival time at individual house and building, which is beyond the national agency’s service. In the meeting, some examples of the actual issuance will be introduced. EEW system has been developed by JMA, Railway Technical Research Institute, and National Research Institute for Earth Science and Disaster Prevention.
DE: 7212 Earthquake ground motions and engineering seismology
SC: Seismology [S]
MN: 2007 Fall Meeting