OCEAN CITY — There were more questions than answers late yesterday about what caused the ground to shake and buildings to rattle in the Ocean City area shortly before noon on Thursday, but Maryland Geological Survey officials have confirmed the data collected at various seismic stations in the area is not consistent with an earthquake.
Just before noon on Thursday, there were dozens of reports of possible seismic activity from Ocean City to Ocean Pines to Bishopville and southern Sussex County and beyond as local residents reported loud booms and homes and businesses shaking for as long as 10 seconds and as many as two different times. The Maryland Geological Survey around mid-day yesterday confirmed there had been “earth motion activity” registered in the area around the same time the reports started flooding in.
“The Maryland Geological Survey (MGS) has identified earth motion activity around the same time and we have asked seismologists in the area to analyze the data further,” said MGS Director Richard Ortt on Thursday afternoon. “We have two separate teams of seismologists looking at the date from our seismometer in Reisterstown and several seismometers in the surrounding states including Delaware, Virginia, New Jersey and Pennsylvania.”
Later on Thursday, Ortt reported the possibility of an earthquake in the area had all but been ruled out.
“Seismologists at Columbia University have analyzed the data from three area stations at Reisterstown, the Eastern Shore and Lewes and have advised that data from those sites is not consistent with an earthquake,” he said. “Very small scale events were observed at the seismic stations, however the signatures and travel times between the stations are inconsistent and do not follow the known travel times of seismic or earthquake events.”
Essentially, the MGS by late Thursday had acknowledged tremors had occurred, but was not prepared to determine just what had happened. “Unfortunately, it was not picked up by any other reporting seismic stations in the area, so there is no consensus as to what the event was or where it originated,” a message from MGS read.
From the beginning, there was speculation the loud booms and subsequent shaking were caused by sonic booms, possible from activity at Wallops Island on the Virginia coast just south of Ocean City and Assateague, or by military jets passing over the mid-Atlantic coast or conduction training and maneuvers. However, Wallops Island spokesman Keith Koehler said on Thursday afternoon there was nothing going on at the facility that would have caused sonic booms. The Patuxent Naval Air Station in southern Maryland conducts training exercises over the Atlantic off Maryland’s coast from to time, but it is uncertain if there were any exercises being conducted on Thursday.
In November, distant rumblings were heard and felt across much of Worcester County including Ocean City causing concerns in the area about a potential earthquake or other seismic activity. However, it was determined the loud booms and window rattling were the result of the U.S. Navy practicing simulated carrier landings for two large aircraft at Wallops. The sonic booms were the result of a new partnership between the Navy and Wallops allowing for the practice of simulated, land-based aircraft carrier landings on a modified airstrip at Wallops. The two twin-engine turboprops are expected to conduct up to 20,000 passes this year at Wallops.