Californians are getting more time to act in the next major earthquake. The U.S. Geological Survey has improved its ShakeAlert system to include satellite data.
This will let people know how big the earthquake is and where it’s centered a lot sooner.
As it stands now, alerts are sent to phones when the magnitude is four-point-five or larger, giving people just seconds to find cover. But the GPS sensors aim to provide an even earlier warning.