People standing above the epicenter of a large earthquake will feel the ground shaking before people on the periphery of the quake. The same can be said of their smartphones.
Researchers at the U.S. Geological Survey are trying to figure out whether smartphones might be used to give earthquake warnings.
Ben Brooks, with the USGS, says if a computer was checking for simultaneous movement of a large number of smartphones, it could give people on the periphery of a quake a 10-or-20-second warning.
He says that's enough time to stop a surgeon from starting an operation.
"Or if you're a bullet train that would like to stop. Or if you'd like to automatically shut-off gas valves," Brooks says. "You can imagine all kinds of scenarios. Or if your kids are trained at school, when they hear the sound to get under their desks."
Researchers at CalTech have tried a similar system. But it didn't work because phone makers filtered GPS data. That means the earthquake movement was filtered and therefore didn't register.