Thursday's non-quake highlighted the need for better earthquake-warning tools. Three western states have a system in place, but Nevada isn't included.

Robert DeGroot, operations team lead for the USGS-managed ShakeAlert Earthquake Early Warning System, told SFGATE that at least four sensors across Nevada detected motion, leading to an automated warning sent out via MyShake Alert to a large portion of California.

A shake alert went out over the U.S. Geological Survey's early warning system on Dec. 4, warning that a 5.9 earthquake near Carson City in western Nevada could produce heavy shaking in the region. But moments later, the survey announced the alert, which was sent to people as far west as San Francisco, was a false alarm.

Dr. Angie Lux is a project scientist with the Berkeley Seismological Laboratory, which helped develop the MyShake app. She told KCRA 3 News that the lab has a network of seismic sensors that go from Mexico to Canada on the West Coast.

The false alert Thursday mistakenly claimed a magnitude 5.9 earthquake had struck near Carson City, Nevada. Here’s what happened.