Facebook's crisis feature that lets users mark themselves safe is called Safety Check.
Facebook introduced Safety Check in 2014 after natural disasters and other emergencies showed how difficult it could be for people to contact friends and family. When activated for a qualifying crisis, the feature can prompt people in an affected area to confirm that they are safe. Users can then notify Facebook friends without having to send individual messages.
The tool has been used during events including earthquakes, terrorist attacks, hurricanes, and other disasters. Its purpose is reassurance and communication, not emergency rescue or official evacuation guidance. A safety confirmation should therefore complement, rather than replace, instructions from local authorities.
The feature is sometimes confused with Facebook Alerts or general crisis-response pages. Those may distribute information or organize support, but Safety Check specifically centers on a person’s status and notifying their network.