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2024年1月1日 能登半島地震 (M7.6)の緊急地震速報
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1.地震について (Earthquake Information)
この地震は、石川県を中心に多大な被害をもたらしました。被災された方々に心よりお見舞い申し上げます。また一刻も早い復興を心よりお祈り申し上げます。一般向けの緊急地震速報は、最初にP波が観測されてから6秒後、地震発生7秒後に能登地方に発信されました。 気象庁の発信状況によれば、震源近傍の20-30kmの範囲では、S波の到着に速報が間に合いませんでした。しかしながら、揺れが数分続いたことを考慮すると、揺れ始めの段階で速報が発表されたことは強い揺れに対して身構える上で効果があったと考えられます。 直後の16:18のM6.1の余震でも緊急地震速報を発表しており、おおむね適切に動作したと考えられます。
This earthquake has caused severe damage, especially in Ishikawa Prefecture. We would like to express our deepest sympathies to those who have been affected by the earthquake. We also pray for the earliest possible recovery.
The earthquake early warning for the general public was sent out to the Noto region 6 seconds after the first P-wave was observed and seven seconds after the earthquake occurred. According to the JMA's warning history, the earthquake early warning did not arrive in time for the arrival of the S-wave in the 20-30 km range near the epicenter. However, considering that the shakings lasted for several minutes, the fact that the warning was issued at the beginning of the S-wave was effective in preparing for strong shakings.
The earthquake early warning was also issued for the M6.1 aftershock at 16:18, and the system was considered to have generally worked properly. -------------------------------------------------------------------
2024/01/01,16:10:22.57 37.496 137.270 15.9 7.6
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Table1. Earthquake information. Origin time, Epicentral latitude, longitude, depth, and JMA magnitude from the left.(ref. JMA catalog)
Fig.1. Event location.
2.観測点分布 (Station Distribution)
Fig.2. Station Distribution.
3.緊急地震速報発信状況 (JMA Earthquake Early Warning Report)
--------------------------------------------------------------------------------------------[01] 24/01/01-16:10:08 5+ M5.5 37.5N 137.2E 010km (24/01/01-16:10:16)
[20] 24/01/01-16:10:08 07 M6.6 37.5N 137.2E 010km (24/01/01-16:10:43)
[30] 24/01/01-16:10:08 07 M7.4 37.6N 137.2E 010km (24/01/01-16:11:07)
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（左から順に情報番号，震源時，最大予測震度，マグニチュード， 震央緯度，震央経度，震源深さ，電文発表時刻） from CEORKA
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Table2. Earthquake early warning reports. Information ID, Origin time, Maximum Intensity, JMA magnitude, Epicentral latitude, longitude, depth, and time to issue the report from the left.(ref. The Committee of Earthquake Observation and Research in the Kansai Area)
気象庁による緊急地震速報の内容 (JMA EEW performance of this earthquake)： 予報・ 警報
4.観測記録 (Observed Records)
Fig.2. Peak Ground Acceleration (left) and Peak Ground Velocity (right).
Fig.3. JMA shaking intensity.
Fig.4. Seismic activity of past 40 years.
5.解析結果 (Results of the IPFx method)
Fig.5. Time history of the estimates for source parameters by the IPFx method. The horizontal axis shows the time of processing.
- upper left: error of epicenter against the final estimation
- upper right: JMA magnitude (black) and maximum estimated shaking intensity (red)
- lower left: epicenter depth
- lower right: automatic picking time (black) and theoretical arrival time (red)
Fig.6. Simulation of the IPFx method. The triangles show seismic stations, and colored triangles are triggered stations. The star shows the estimated location of an earthquake. The color of the samples is proportional to the likelihood of the hypocenter location.
Fig.7. The waveforms aligned from the epicenter estimated by the IPFx method.
Fig.8. The velocity waveforms at ISK002 station.
Acknowledgements:
気象庁の震度情報、防災科学技術研究所のK-NET,KiK-net,Hi-net,S-netの波形、気象庁の強震波形、一元化震源カタログを利用しました。
緊急地震速報を発表した地震の解析結果
山田真澄 ホーム