The company described the feature as "a simple and easy way to say you’re safe and check on others," and said that in disasters: "communication is most critical both for people in the affected areas and for their friends and families anxious for news."
The feature lets users alert their friends and family to the fact they're safe, check on others caught in the affected area, and mark their friends as safe.
Only friends will be able to see the safety check updates, and it will be rolled out globally on Android, iOS, feature phones, and desktop, the company said.
The tool becomes activated when Facebook detects a user is in an area affected by a disaster, using either the city they've listed in their profile, the last city they were located in if they had signed up for their "Nearby Friends" project, or the last location they logged onto the internet. A notification is sent to that user, asking if they're safe.
If Facebook gets the location wrong, users can mark themselves as outside the affected area.
If the user is safe, they can click the "I'm Safe" option, which will generate a notification and news feed story. Users can also mark friends as safe.
Once the tool is activated, users will also receive a notification about friends who have marked themselves as safe too. Clicking the notification will take users to a list which shows the updates.