'This is wild,' USGS says of Dover 4.1 earthquake

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A 4.1 magnitude earthquake struck Kent County late Thursday afternoon.

The quake struck about 7 miles northeast of Dover Air Force Base at 4:47 p.m., according to the U.S. Geological Survey. It was originally labeled magnitude 4.4 before the USGS lowered the scale of the temblor.

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The Delaware Emergency Management Agency believes the epicenter was in Bombay Hook National Wildlife Refuge.

"There are no reports of damage or injuries at this time," DEMA spokesman Gary Laing said.

The USGS said it received more than 6,500 responses within an hour of the quake from people who felt the temblor throughout the Mid-Atlantic — as far south as suburban Washington, D.C., and as far north as the Poughkeepsie, New York, area.

A geophysicist, Cheng Shengzao, with the USGS, said the East Coast quake was surprising.

“This is wild. It’s not often that this happens,” Shengzao said.

A 3.3 magnitude earthquake hit just east of Dover in 1879, according to the Delaware Geological Survey.

An earthquake of strength that hit Thursday is considered to be moderate and generally results in little damage, the federal agency reports.

“We wouldn’t expect to have damage from an earthquake of this size," said Paul Caruso, a USGS geophysicist based in Golden, Colorado. “We know from the past, even when we have quakes above magnitude 3 on the East Coast, they’re felt pretty far away.”

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Louise Carey, an owner of Carey’s Diesel in Leipsic near the earthquake's epicenter, was in her building’s second-floor office when she heard a “boom.”

Carey and her workers ran out of the shaking diesel engine repair shop believing there had been an explosion or worse yet, a bomb had been detonated.

“The boom is what scared everyone to begin with,” she said. “I’d never experienced that loud boom and then there was like a roaring or a rumble.”

“It happened quick.”

Outside the shop, Carey said they could see the building shake. And while several items fell to the ground, nothing was damaged – this includes the boats in their boatyard a couple of blocks away.

“Everything was OK.”

“I’m 74-year-old and believe me, it scared me,” she said, adding this was the third quake she’d been in, including the 2011 tremor and one in Latin America. “And I don’t care to be in another one.”

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Jana Pursley, also a geophysicist with the USGS, said earthquakes can happen anywhere at anytime. Within the tectonic plates “intraplate earthquakes” are stresses within the plate that are less frequent than fault line earthquakes — where two plates meet.

Pursley explained that the audible rumbling is the vibrations the human ear can detect.

“Earthquakes are just vibrations,” Pursley said. “They are just like loudspeakers when they vibrate.”

Shallow quakes usually have a sharp bang, she added, and a deeper one has a rolling rumble. Thursday's earthquake center was at a depth of about 5 miles.

In downtown Dover, people streamed out of buildings minutes after the quake, most looking for the source of the disturbance.

"I was in the library when I felt the shaking," said Rick Kozakowski of Dover. "I knew it was either an earthquake or Godzilla."

Angie Coulter was sitting on her couch in Dover when she said she heard a noise like a train crash.

“We live by the railroad, so I just thought it was an accident,” Coulter said.

She felt the floor start to shake for less than 30 seconds. Immediately, Coulter said, she thought something was happening below the house.

“I thought the house was going to collapse, and then it stopped,” Coulter said.

Kay Sass, public affairs and emergency management coordinator for Dover, said the earthquake shook the building and “we felt it pretty well at City Hall.”

She said there were no reports of damage and no interruption of services in the city.

“We first had to figure out what it was and then we checked to make sure the building was OK,” she said.

The quake struck just as Dover residents were preparing the city's Capitol Holiday Celebration and tree lighting, an event Mayor Robin Christiansen said “started with a bang.”

"I was at my brother-in-law's house and at first I thought his heater blew up because the whole house shook," said Debby Messina. "We went outside to see if a plane crashed and all of his neighbors were outside too."

A member of Dover Air Force Base Public Affairs said there were no injuries, no significant damage to government property and no interruptions to anything out there. “No change in operations.”

Laing said residents should only call 911 to report damage or injuries and urged people not to tie up emergency lines to ask if an earthquake occurred.

Dover Police Department spokesman Cpl. Mark Hoffman said his agency has fielded many calls from city residents asking what the tremor was, some he described as “panicked.”

He said the police department has not received any reports of damage or injuries.

While fixing a guitar on the third floor of his house on Wilmington's North Franklin Street, Rob Pfeiffer suddenly heard wine bottles shaking and he knew.

“I lived in L.A. on the San Andres fault, so I immediately knew it was an earthquake,” he said.

In Ocean View along Delaware's coast, the sensation was just as intense. Carole Verona was startled from reading Facebook and a book in her living room on the top floor of her stilt house.

"It felt like someone was downstairs shaking the pilings for 20 seconds," she said. "The ornaments on our (Christmas) tree rattled a little bit. (We thought), 'Oh no, our pilings are going to slide into the lagoon.' "

Tom Harmon of Smyrna was on his way to pick up his wife Mary from Wesley College's Johnston Hall when the quake struck, a rumble he initially mistook for someone getting too close to his bumper.

"We thought an elevator crashed," Mary said. "I called security and they said they thought it was an earthquake so I was actually relieved."

Thursday's quake was the second to hit the Mid-Atlantic in less than 10 years. A 5.8-magnitude earthquake centered in Virginia shook homes throughout the Mid-Atlantic on Aug. 23, 2011.

"This one felt a lot different," Messina said. "That one felt like I had vertigo. This one shook everything."

Lois LaMarche, who has lived in the Sherwood neighborhood of Dover for 43 years, agreed that this earthquake was different.

"That was just a little rumble," she said. "There was no comparison.”

John Grooby and his wife, tourists from England visiting their son, said they missed the whole thing.

"We were in the car heading to the tree lighting," he said. "We didn't find out about it at all until we heard people talking about it. I guess we missed the excitement."

The story will be updated as more information becomes available.

Staff writers Esteban Parra, Josephine Peterson and Jeremy Cox contributed to this report.