Emergency alert system

An emergency alert system distributes urgent warnings to people in a defined area or population. It uses communication channels to convey hazards, protective actions, and updates.

Cell Broadcast: A mobile-network method that sends messages to compatible phones within selected cell coverage areas. It delivers geographically targeted warnings without requiring phone numbers or individual subscriptions.
Tsunami warning: An official notice that a tsunami may affect a specified coastline or region. Tsunami alerts must convey evacuation urgency before waves reach exposed shores.
Protective action decision model: A framework describing how people interpret hazard warnings and decide whether to take protective action. It explains why receiving an alert does not automatically produce a safe response.
Reverse 911: An automated telephone notification service that calls numbers associated with a selected geographic area. Unlike broadcast alerts, it contacts a database of landline or registered phone numbers.
Wireless Emergency Alerts: A United States system that sends brief emergency messages to compatible mobile devices in designated areas. It is a prominent national implementation of location-based alerts on mobile phones.
Tornado warning: An official notice that a tornado has been sighted or indicated by radar in a specified area. Short lead times make fast, locally targeted delivery essential.
False alarm: An alarm issued when the hazard it signals is absent or does not occur as expected. Repeated false alarms can weaken trust in later emergency messages.
Emergency notification system: A service that sends alerts to a defined group, often using subscribed contact details. Opt-in notification services reach enrolled users rather than every compatible device in an area.
Common Alerting Protocol: An XML-based standard for exchanging consistent alerts across warning systems and communication networks. A shared message format helps one warning reach multiple channels with consistent information.
Amber Alert: A public alert requesting help locating a child believed to have been abducted and endangered. It applies alert infrastructure to a time-critical search for a missing child.

Linked from 14 pages