"We want to provide a helpful tool that people can use when major disasters strike, so we've created 'safety check' -- a simple and easy way to say you're safe and check on others," a Facebook blog post said late Wednesday.
Facebook said it began working on the system after the Japan disaster: "During that crisis, we saw how people used technology and social media to stay connected with those they cared about," the statement said.
The new tool expands on its "disaster message board" used in Japan.
In "safety check," users in areas affected by a disaster will get a notification asking "Are you OK?"
Users can select to click "I'm safe" and status updates will be sent to friends.
Facebook will use a user's smartphone location to determine if someone is affected by a catastrophe, while allowing people to correct any location mistakes.
"Unfortunately, these kinds of disasters happen all too frequently," Facebook said.
"Each time, we see people, relief organizations and first responders turn to Facebook in the aftermath of a major natural disaster."
Facebook said the tool will be available globally on Android, iOS, feature phones and desktop.
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