Emergency Warning Broadcast System (Japan)

Emergency Warning Broadcast System, omitted as EWBS or EWS (緊急警報放送, Kinkyū keihō hōsō) is a warning broadcast system in Japan that is performed by automatically turning on the switch of a television/radio receiver in a standby state by using a specific signal. This is done when a large-scale disaster such as an earthquake occurs or when a tsunami warning is announced, and it is intended to help prevent or mitigate the damage caused by the disaster.

Source: Wikipedia — Emergency Warning Broadcast System (Japan) (CC BY-SA 4.0)