Shake map showing where 4.1-magnitude quake near Dover, Del. was felt on Nov. 30. (USGS)

A rare magnitude 4.1 earthquake occurred in eastern Delaware, about six miles northeast of Dover, at 4:47 p.m. eastern Thursday. The tremor was centered in Bombay Hook National Wildlife Refuge along the Delaware Bay.

Reports compiled the U.S. Geological Survey (USGS) indicate the quake was felt as far west as the Washington D.C. area and as far north as Allentown, Pa., New York City and southern Connecticut.

Julia Reinstein, a reporter for Buzzfeed News, tweeted that a spokesperson for the Dover Police Department in Delaware said there were no reports of damage or injuries.

Capital Weather Gang readers on Twitter reported feeling the tremor around Washington and particularly its northern suburbs, including Aspen Hill, Columbia, Gaithersburg, Olney, Severna Park and Silver Spring and even McLean in Virginia. There have not been reports of any damage locally as of this time.

“Whole house shook and dog went wild,” tweeted @kaeperr in Gaithersburg, Md.

Dale Grant, a geophysicist at the U.S. Geological Survey, said an earthquake in this location is “exceptionally rare” and that he was not aware of any previous activity in the area but that he needed to further investigate. “We’re just getting the information in now.”

The Dover area is positioned in a relatively low risk zone for earthquakes according to a USGS hazard map.


(USGS)

Data from the USGS suggest only three earthquakes magnitude 4.0 or higher have occurred between Washington and New York since 1950. This 4.1-magnitude quake would tie as the largest on record in the state of the Delaware.

A magnitude 5.8 earthquake centered in Mineral, Va. shook the D.C. region in 2011 and was approximately 50 times as big and 350 times as powerful as Thursday afternoon’s quake near Dover.

Thursday’s quake was the second to be felt in the greater D.C.-Baltimore region in the past six weeks. A very small 1.5-magnitude tremor occurred between Olney and Sykesville, Md. on Oct. 30.

Please let us know if you felt Thursday’s earthquake and your location in the comment area, and if you are aware of any damage.

(Note: the USGS initially rated the earthquake 4.4, then upgraded it to 5.1, and then downgraded it to 4.4 and 4.1 hence the changes to this story.)