Its epicenter was in Berkeley, across the bay from San Francisco, but was felt up to 40 miles away.
"It's possible", he said of a bigger natural disaster occuring."[But] the chances of this quake foreshadowing a larger event, goes down quicker over time.
The quake knocked items off the 24-hour Safeway's shelves in San Leandro.
The historic luxury hotel had no damage, an employee said, declining to give her name. "It just rocked the room and bed like two or three times quickly with a decently loud rumble in North Berkeley", Dale Fest wrote on the San Francisco Chronicle's Facebook page.
It was felt widely across the Bay Area and woke everyone up.
East Bay residents are being warned to look out for aftershocks, which can happen days and weeks after a quake.
"The real question is: is this a foreshock to something larger?" Don Drysdale, Spokesman for the California Geological Survey, discussed the current quake and what people should be aware of.
The epicenter was in Berkeley just across the bay from San Francisco
'We live in quake country so we should do all the things they tell us to do, ' Knudsen said.
The quake is said to be associated with the Hayward fault, which aligns underneath the eastern side of the Bay area - from Hayward through Berkeley. "How active is the Hayward Fault?". Though the last big quake on the fault was a magnitude 7 in 1868, they are concerned about the recurrence rate which gauges how often you would expect a big natural disaster to happen on a given fault.
The last major quake along the Hayward fault happened in October of 1868, when a magnitude 6.8 hit the San Francisco Bay region, making it the most destructive natural disaster in the state's history. Thirty people died then and there was extensive damage.
There hasn't been a major natural disaster on the Hayward Fault in over 100 years.
The natural disaster was centered north of the Claremont Hotel and was caused by movement on the Hayward fault, which runs from San Pablo Bay to Fremont.
The USGS calls the fault a "tectonic time bomb" which could "cause hundreds of deaths, leave thousands homeless and devastate the region's economy".