Smartphones provide early-warning system.

• Position: Earthquake Alerts

While you are checking your e-mail, scrolling through social-media feeds, or just going about your daily life with your trusty smartphone in your pocket, the sensors in that little computer also could be contributing to an earthquake early-warning system--so says a study led by researchers at the California Institute of Technology Pasadena, and the U.S. Geological Survey, Reston, Va. The study suggests that all of our phones and other personal electronic devices could function as a distributed network, detecting any ground movements caused by a large earthquake and, ultimately, giving people crucial seconds to prepare for a temblor.

"Crowd-sourced alerting means that the community will benefit by data generated by the community" says Sarah Minson, a geophysicist with USGS and lead author of the study. Minson completed the work while a postdoctoral scholar at Caltech in the laboratory of Thomas Heaton, professor of engineering seismology.

Earthquake early warning (EEW) systems detect the start of an earthquake and rapidly transmit warnings to people and automated systems before they experience shaking at their location. While much of the world's population is susceptible to damaging earthquakes, EEW systems currently are operating in only a few regions around the globe, including Japan and Mexico.

"Most of the world does not receive...