Dover International Speedway officials report the track and its staff are safe and sound after a 4.1-magnitude natural disaster shook the DE facility around 4:47 p.m. ET Thursday afternoon.
The natural disaster hit at 4:47 p.m.
It was followed up ten minutes later by a less powerful 5.0 aftershock in the same area, the survey said.
Social media was abuzz even before the official word from scientists.
The Associated Press writes that downtown Dover was in a flurry as lawmakers and workers in the statehouse went outside to see what happened.
The USGS downgraded the quake from a 5.1 to a 4.4 on the Richter scale.
There were no immediate reports of injures.
Twitter users, including History Professor Kevin Kruse, also feeling the quake in Princeton.
"I was talking with the other seismologists and we said, 'Wow, we don't ever remember a quake in DE", he said. "Usually the largest aftershocks we see in a series is about 1 magnitude smaller than the main quake". "It was actually pretty scary and pretty surprising".
Hundreds of people said they felt it. Carberry, who is from the West Coast, said she told co-workers, "I'm pretty sure this is an quake".
Iran has experienced at least two major quake disasters since - one in 2005 that killed more than 600 people and another in 2012 that left some 300 dead. It caused damage to public buildings, pipes and monuments, most notably the National Cathedral and the Washington Monument.