Federal officials say two nuclear reactors at the North Anna Power Station in Louisa County, Va., were automatically taken off line by safety systems around the time of the earthquake.
The Dominion-operated power plant is being run off three emergency diesel generators, which are supplying power for critical safety equipment. The NRC and Dominion are sending people to inspect the plant.
A fourth diesel generator failed, but it wasn't considered an emergency because the other generators are working, according to the Nuclear Regulatory Commission.
Dominion said it declared an alert at the North Anna facility and the reactors have been shut down safely and no major damage has been reported.
The earthquake was felt at the company's other Virginia nuclear power station, Surry Power Station in southeast Virginia, but not as strongly there. Both units at that power station continue to operate safely, Dominion said.
The quake also caused Dominion's newest non-nuclear power station, Bear Garden in Buckingham County, to shut down automatically.
NRC spokesman Roger Hannah says the agency was not immediately aware of any damage at nuclear power plants in the southeast.
Hannah said he knew of no other shut reactor but that unusual events were reported at a dozen other plant sites.
Louisa County is about 40 miles northwest of Richmond.