National Emergency Message
A National Emergency Message (SAME code: EAN), previously known as an Emergency Action Notification (1971 - circa 2022), is the national activation of the Emergency Alert System (EAS) used to alert the residents of the United States of a national or global emergency such as a nuclear war or any other mass casualty situation. This alert can only be activated by the president of the United States or a designated representative thereof, such as the vice president.
Source: Wikipedia — National Emergency Message (CC BY-SA 4.0)