This is Scientific American 60 Second Science.

I'm Cynthia Graber.

Got a minute?

Early warning systems can be the difference between life and death in earthquake-prone

regions, but they're expensive.

The US, Mexico, and Japan have such systems that leaves large swaths of Central and

South America, Asia, and the Caribbean unprotected.

Now scientists think one solution could be hiding in our pockets are cell phones.

Smartphones employ the latest GPS technology.

So scientists tested arrays of smartphones to determine if they could measure

displacement caused by the Earth's shaking

and signal the subtle beginnings of an earthquake.

For the experiment, the researchers used a hypothetical

magnitude 7 earthquake in California

and data from the real magnitude 9 earthquake off the coast of Japan in 2011

that led to the tsunami that caused the nuclear accident at Fukushima.

They found that as few as 500 cellphones in California

could alert the public five seconds before an event,

enough time to at least move to a less vulnerable part of a room or dive under a desk.

For the Japanese earthquake, early warning would not have helped in the region closest

to the epicenter, but such an alert could have

helped cut damage in downtown Tokyo, and the information would have reached the coastline

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