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Title: J-Alert  
Author: World Heritage Encyclopedia
Language: English
Subject: Emergency population warning systems, NHK, NTT DoCoMo, Earthquake Early Warning (Japan)
Publisher: World Heritage Encyclopedia


Diagram of the J-Alert system

J-Alert (全国瞬時警報システム Zenkoku Shunji Keihō System) is a nationwide warning system in Japan launched in February 2007. It is designed to quickly inform the public of various threats. The system was developed in the hope that early warnings would speed up evacuation times and help coordinate emergency response.

The system

J-Alert is a satellite based system that allows authorities to quickly broadcast alerts to local media and to citizens directly via a system of loudspeakers. According to Japanese officials it takes about 1 second to inform local officials, and between 4 and 20 seconds to relay the message to citizens.

All warnings, except for severe weather warnings, are broadcast in five languages: Japanese, English, Mandarin, Korean and Portuguese (Japan has a small Chinese, Korean and Brazilian population). The warnings were broadcast in these languages during the 11th March 2011 earthquake and tsunami. The severe weather warnings are only broadcast in Japanese.

J-Alert broadcasts via the Superbird-B2 communication satellite.

Information able to be transmitted by this system

  • Earthquake
    • Earthquake Early Warning
    • News flash of hypocenter, magnitude, and precaution to tsunami
    • Information of hypocenter, magnitude, intensities of various cities, and presence of tsunami
    • Advisory information of Tokai earthquakes
    • Earthquake prediction information of Tokai earthquakes
    • Caution to Tokai earthquakes
  • Tsunami
  • Volcano eruption
  • Military threats

Adoption rate

Many prefectures and urban areas have been slow to adopt the system. Upon its introduction the Japanese government hoped to have 80% of the country equipped with the J-Alert system by 2009. However, under current plans, by 2011 only 36% of the nation will have been covered. Cost has been a major factor. The initial installation estimate is estimated to be around 430 million yen, and the yearly maintenance is estimated to be around 10 million yen. Local governments have been hesitant to cut other services to implement the system.


External links

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