The rumbling could be felt all across the city.
An earthquake centered between NYC and Philadelphia rattles much of the Northeast
"Did you feel that?" Regina Syikes said her friend asked as she visited her in South Philadelphia. "And I'm like, 'It's Leo!' I have a husky and he was running around."
Syikes wasn't the only one who, initially, said she was confused as to what was happening.
"I was on a call with a colleague and I was like, 'I think I have to go, my entire house is shaking.' And then I thought it was a large truck coming down my street. It wasn't," said Kelsey Demerlis from Fishtown.
Viewer videos capture the moment a 4.8 magnitude earthquake shook the region
The epicenter of the earthquake was in Hunterdon County, New Jersey, but Philadelphians like William Glover, who was asleep when the shaking started at 10:23 a.m., felt it too.
"So I woke up, thought I was tripping. My mom came in and was like, 'You feel that?' And I was like, 'Okay, as long as I ain't crazy,'" he said.
"We too were wondering, 'Did you feel that? What was that?'" said Dom Mireles, the director of the Philadelphia Office of Emergency Management.
He said workers in the office at 2nd and Spring Garden felt the tremble and sprang into action, activating an emergency response.
"Your city and our administration is responding to this event swiftly and surely," said Mayor Cherelle Parker.
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The mayor says city agencies worked together and found no reportable damage in municipal buildings, schools or transportation. Still, officials say everyone needs to remain alert for the possibility of aftershocks.
"Drop, hold on, and take cover. Protect yourself by dropping on your knees and your hands. Hold onto something sturdy like a table or desk and cover your head and neck with your arms," said Mireles.
Mireles says if you happen to driving during an earthquake, pull over and set the parking brake.