U.S. scientists use Twitter to track earthquakes

Tweets from Chile's 8.3-magnitude earthquake last month.

When earthquakes happen, U.S. government scientists get a 60-second heads up from an unlikely partner -- Twitter.

Since 2009, seismologists at the U.S. Geological Survey have teamed up with the social media company. The result? More accurate emergency alerts.

And it all relies on you, the public. If you tweet "earthquake" -- even if it's in seven other languages -- you're helping American scientists get better at tracking these destructive phenomena.

It's called Tweet Emergency Dispatch. Twitter described the program in a blog post on Wednesday, and U.S. government scientists confirmed it to CNNMoney.

Here's how it works. USGS pays Twitter to tap into its data. A program automatically sorts through the tweets coming from Twitter's 316 million active users. When, all of a sudden, lots of people in a specific area start sending out messages about earthquakes, government researchers get an alert.

"It's not a revolutionary change in what we do, but it just gives us that extra minute to start on our response," said Paul Earle, a seismologist at the federal agency.

That extra bit of Twitter data does a few different things. Sometimes, it alerts scientists to an earthquake that faulty sensors didn't pick up. Other times, it catches earthquakes in places where there weren't any sensors at all.

After all, the USGS National Earthquake Information Center in Golden, Colorado has 2,000 devices listening to tiny movements in the Earth's crust, but only about half of those are outside the United States.

For example, last year, seismic sensors in California picked up a magnitude 5 earthquake -- a slight rumble. USGS automatically placed the alert on its website. But when Earle looked through his Twitter alert system and didn't see any unusual chatter, he realized something was wrong. It turns out that earthquake never really happened.

"That's the key," Earle said. "The data stream from Twitter is totally independent. It's a secondary check."

Dozens of earthquakes in the last few years have helped scientists fine-tune the system. They've gotten better at ignoring irrelevant tweets -- like news stories and everyday conversations about earthquakes. As can be expected, the most relevant tweets are curt and to-the-point.

During violent shaking, people don't have time to write long tweets.

USGS has also learned to look for certain words. Spanish speakers use the word "terremoto" for major quakes but "temblor" for smaller ones.

In a company blog post, Twitter employee Elaine Ellis recounted a visit USGS center in Colorado. Earthquake aftershocks rumbled in Chile. In just over a minute, 14 people had tweeted about it -- and American scientists immediately got an email alert.

Next up? Government seismologists want to redirect Twitter-based alerts directly to earthquake sensors. The idea is to turn up the sensitivity level of sensors the second that people start feeling the ground shake -- making readings even more accurate than before.

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