J-Alert (Japanese:J－ALERT/Jアラート,romanized: J Arāto; full name全国瞬時警報システム,Zenkoku Shunji Keihō Shisutemu,'National Early Warning System') is theearly warning system used inJapan. J-Alert was launched in February 2007.[1] The system is designed to quickly inform the public of threats and emergencies such asearthquakes, severe weather, and other dangers. The system was developed in the hope that early warnings would speed up evacuation times and help coordinate emergency response.[2]
J-Alert is asatellite based system that allows authorities to quickly broadcast alerts to localmedia and tocitizens directly via a system of nationwideloudspeakers,television,radio,email, andcell broadcasts.[3] According to Japanese officials, it takes about one second to inform local officials, and between four and twenty seconds to relay the message to citizens. An enhanced version of the J-Alert receivers were installed by the end of March 2019. The new models can automatically process the information within two seconds, compared to the older models that can take up to twenty seconds.[4]
J-Alert broadcasts via both ground systems and theSuperbird-B3 communication satellite.[5]
When there is a civil emergency such as a ballistic missile heading towards Japan, a siren called Civil Protection Siren sounds across loudspeakers.[6]
Many prefectures andurban areas were slow in adopting the system. Upon its introduction, the Japanese government hoped to have 80% of the country equipped with the J-Alert system by 2009.[2] However, by 2011, only 36% of the nation had been covered. Cost had been a major factor; the initial installation is estimated to be around 430 millionyen, and the yearly maintenance is estimated to be around 10 millionyen.
By May 2013, 99.6% of municipalities nationwide were covered.[7]