The U.S. Geological Survey reported a 4.7 earthquake 136 miles off the coast of Ocean City early Tuesday night.
The quake hit around 6:30 p.m., and occurred just over 6 miles deep.
State geologists said Wednesday that they believe an underwater landslide or “reactivation” of an ancient fault might have triggered it, but that they had not confirmed the cause.
A firefighter in Ocean City said he had not felt any tremors or related calls for service Tuesday. But dozens of people reported feeling the earthquake to the USGS. The responses came from locations across the East Coast, including Ocean City; Berlin; Dewey Beach, Del.; Norfolk, Va.; the Outer Banks in North Carolina; and even as far away as Massachusetts.
Several people in the Baltimore area reported feeling the earthquake as well. Overall, the reports recorded a low level of intensity.
In a Facebook post, Ocean City town officials said emergency officials were monitoring the situation but had not observed any effects from the quake.
No tsunami warning has been issued.