The clusters of earthquakes have all been underneath the East Bay suburb of San Ramon, which is close to the Calaveras fault. There were at least 19 earthquakes of magnitude 2 or greater on Monday alone.

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.

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.

CONTRA COSTA COUNTY, CA - A preliminary 2.2 magnitude quake was reported near San Ramon Monday morning, according to the U.S. Geological Survey.

For anyone already travelling in Japan - or planning to - here is what you need to know to stay safe and navigate responsibly during an earthquake.

The quake came during a cluster that saw over a dozen other earthquakes reported over a 24-hour period, the USGS map shows.

People in the Bay Area continue to experience the “flare up” of earthquakes into Monday afternoon, Oakland being the latest city to experience a jolt.