Washington (CNN) -- President Barack Obama told reporters Friday he did not feel the earthquake that rattled parts of suburban Washington early in the morning.
The rare quake, which struck about 5 a.m., was centered about 20 miles northwest of the capital, the U.S. Geological Survey said. It had a magnitude of 3.6 -- relatively mild by earthquake standards but stronger than any other quake to shake the region in the past 35 years, the agency said.
Steve Dolce, a CNN technical manager, said his house in Germantown, Maryland, "vibrated slightly" for about 10 seconds.
"I looked out the window ... wondered if it was a plane or something, then I checked my BlackBerry and saw a dozen e-mails alerting the small quake," he added.
The earthquake was the first with a magnitude of more than 3 near Washington since 1974, said Amy Vaughan, a geophysicist at the USGS National Earthquake Information Center.
"This is a significant event for the region," she said.
About an hour after the quake, Vaughan said, more than 5,500 people had reported feeling it across Maryland, in nearby Washington, and in states including West Virginia, Virginia and Delaware.
"It was really loud, like a plane flying really low. I had never felt anything like it," said Anne Ngunjiri, 30, of Gaithersburg, Maryland. "I was jolted out of bed. All my neighbors woke up. After it passed, I thought it could be an earthquake, and lay in bed hoping there were no aftershocks."
Judy Rudolph, 64, said she was writing e-mails in bed in Rockville, Maryland, when her house started to shake.
"My first reaction was the noise ... I thought it was an explosion," she said.
She said she'd never felt anything like it in her 31 years living there.
Until Friday, the largest earthquake recorded within about 50 miles of Gaithersberg since 1974 was a 2.7-magnitude quake in 1993, Vaughan said.
But geologically speaking, she said it was "not completely unexpected" for a 3.6-magnitude quake to hit there.
"Occasionally these things do happen even east of the Rockies, even though it's not really on a plate boundary where we expect earthquakes. ... Faults do exist from when the continent was forming. There are small faults that do exist within this area," she said.
Vaughan said major structural damage was unlikely, but people may experience aftershocks for the next day, or even a week or two after the quake.
Washington's Homeland Security and Emergency Management Agency said no injuries or property damage had been reported.
The last earthquake in Maryland occurred on October 8, 2007, according to the USGS website. It was a 1.7-magnitude quake centered about 5 miles northwest of Baltimore.
CNN's Bob Kovach contributed to this report.