OCEAN CITY, Md. (AP) -- Trembling earth and a mysterious loud noise have startled some residents in Maryland, 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, says 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., says the observatory's seismic stations didn't show any strong signals associated with an earthquake.
A spokeswoman says two supersonic flights left Naval Air Station Patuxent River in Patuxent, Md., on Thursday. Both were routine training events.
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