Seismologists say because the earthquake was a 7.1, the 6.4 magnitude earthquake that hit yesterday is now called a foreshock.
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Shaking was felt all over-from the Central Valley to San Diego and even in San Jose.
Our ABC7 News crew in our San Jose office saw lights swaying and felt light shaking.
"Photojournalist Scott Arthur and I were at the San Jose bureau, working on a completely different story when we felt the earthquake," ABC7 News Reporter, Amanda del Castillo recalled. "I initially thought I was feeling a bit dizzy, before realizing the light fixtures were swaying."
#EARTHQUAKE Our lights at the #SanJose bureau continued swaying for more than minute. @USGS reports a magnitude 7.1 earthquake hit 11 miles from Ridgecrest, CA. Did you feel it? #abc7now pic.twitter.com/UmTAk8YFnL— Amanda del Castillo (@AmandaABC7) July 6, 2019
On social media people corroborated this account and even said they felt it in Alum Rock.
Of course, what was felt in the Bay Area was nothing compared to the power people in Southern California experienced.
RELATED: 7.1 SoCal earthquake 1 of 12 7.0 earthquakes in California history
ABC7 News spoke with USGS officials in Menlo Park.
"The 'big one' is coming, but earthquakes like these are coming too. In fact, this is a more common hazard," USGS Seismologist Sarah Minson said. "The 'big one' is scary, so if it helps you to be less scared, think about these things. They will come more often, they are easy to prepare for and they're easy to recover from."
Minson explained we saw the power of Friday's earthquake fluctuate from 6.9 and 7.1 because new data was constantly being updated.
"Any earthquake is exciting and interesting, but one of this magnitude is probably beyond exciting and interesting, and into being a little bit scary," she added. "Especially for people in the upper central region."
We also spoke with people in the South Bay who said swaying chandeliers caught their attention.
Yvonne Duque and her husband Dario were eating dinner in Downtown San Jose. Yvonne was the first to notice any movement from the light fixtures.
"I go, 'Maybe it was the air conditioner,' but they were swaying," she said.
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"Pretty scary, especially after what happened this week," her husband Dario added. "We were just having dinner, and looking around and all of a sudden I looked up and said, 'Why are all the chandeliers swaying?'"
Minson explained beyond simply experiencing the brief shaking, earthquakes could have a significant psychological impact on people.
"It is documented that after earthquakes people do suffer PTSD-like symptoms and this could be harmful to people," she said.
USGS officials say they expect another large quake, possibly a 6.0, could hit in a few days.