Tremors felt in Ocean City, Md., but no earthquake, officials say

BALTIMORE – Trembling earth and a mysterious loud noise startled some residents in Maryland on Thursday, though officials said it wasn't an earthquake and one expert said it may have been a sonic boom.

Jessica Waters, the communications manager in Ocean City, said her office received dozens of calls from residents starting about noon. Residents also took to social media reporting what they heard and felt.

"We didn't feel anything at city hall," Waters said, but calls came in from all over the resort town and as far west as Berlin, 11 miles away. There were no reports of damage or injuries.

Town officials contacted state and local emergency officials and geological agencies, but the event was not an earthquake, Waters said.

Won-Young Kim, a seismologist with Lamont-Doherty Earth Observatory in Palisades, N.Y., said the observatory's seismic stations didn't show any strong signals associated with an earthquake. The observatory monitors all data from seismic stations across the Northeast, in real time.

"Many felt the disturbance," Won-Young said. "I'm not 100 percent certain, but it's possible it was a sonic boom from a high-speed jet."

Two supersonic flights left the Naval Air Station Patuxent River in Patuxent, Md. Thursday, a spokeswoman said.

Connie Hempel, public affairs officer for the air station, said Thursday that the flights off the Atlantic coast were routine testing and training events. She said the air station "takes precautions to lessen the impact of testing and training activities on the community."

Bob Conkwright, a geologist with the Maryland Geological Survey, said the agency's seismograph near Reisterstown in central Maryland picked up a signal at 11:55 a.m. Thursday, but he said it was not clear what caused it.

"It could have been caused by a tree falling down near the equipment," he said.

The U.S. Geological Survey's website also showed no evidence of an earthquake.