Reports of a tremor, concentrated mostly in Brigantine, first showed up on social media about 1:30 p.m. Jan. 28, 2016.
UPDATE: The U.S. Geological Survey says the shaking was likely from a sonic boom.
Numerous social media users are asking whether the continuing tremors shaking parts of New Jersey are the result of an earthquake, or a seismic blast.
By 3 p.m., the U.S. Geological survey had posted on its website that the tremors shaking parts of New Jersey on Thursday afternoon were the result of a probable sonic boom.
The shaking began at about 1:30 p.m. and prompted residents in counties along the shore to ask what had just happened. Several reports came from NJ Advance Media staff members living near the coast.
RELATED: Earthquake hit N.J. earlier in January
Photographer Lori M. Nichols said that she did not hear anything, but felt her Brigantine home shake at 1:24 p.m. and again at 1:30 p.m. Brigantine residents then felt a third, larger tremor at about 2 p.m., and a smaller one 10 minutes later, according to Nichols.
Readers in Atlantic, Ocean, Cape May and Monmouth counties have also written in to say they felt their houses shake.
"Everybody's outside right now yelling to each other about what it was," Nichols said. "Across the street, someone said their room was shaking."
Barnegat police posted an alert on their Facebook page acknowledging the mysterious tremors.
"We are experiencing some minor seismic activity and we are investigating same," the alert said. "We will update further as we gather more info."
Other police departments in Ocean County as well as the Ocean County Sheriff's Office said they're aware of the tremors but asked residents not to call 911 to report them.
Toms River police said they started receiving calls about the activity around 2:20 p.m. Ralph Stocco, spokesman for the department, said the local military bases "are not reporting any activity that could be associated with it."
In Brick Township, the tremors could be felt on an average of every 4 minutes starting at 1:30 p.m. before they started to subside at 2:40 p.m.
Brick Township police Sgt. Neal Pederen said he doesn't know what was causing the shaking and the department has not been able to substantiate reports that it was an earthquake.
Earthquakes in Galloway Twp. NJ just now. #earthquake #NewJersey
-- Ray Brown (@XRAYMUZIK) January 28, 2016
house just shook twice in #Brigantine, #NewJersey. #earthquake? anyone else at #JerseyShore feel it? #NJ
-- Lori M. Nichols (@PhotogLori) January 28, 2016
Was that an #earthquake in #NewJersey I just felt?
-- Rob Kelly (@robkellysurf) January 28, 2016
The U.S. Geological Survey is responsible for tracking earthquakes around the country. The agency posted online that a sonic boom had been reported in New Jersey at about 2:30 p.m. The USGS notes on its website that often, sonic booms can be mistaken for earthquakes.
The Geological Survey has not yet returned requests for comment.
Theories behind those weird 'booms' in N.J.
Officials with Joint Base McGuire-Dix-Lakehurst reported no activities there that would account for the rumblings. All aircraft operated there are subsonic, so no sonic booms would be produced.
When practice ranges are in use, with large ordnance being detonated, the public is notified ahead of time, explained Tech Sgt. Darrell Dean, with the joint base press office.
"The ranges are clear today," Dean said.
New Jersey State Police have not confirmed the origins of the tremors.
We are not reporting any type of seismic blasts anywhere in NJ. Looking to confirm reports of reported tremors.
-- NJSP - State Police (@NJSP) January 28, 2016
Earlier this month, a 2.07-magnitude earthquake shook the ground in the area of Ringwood.
MaryAnn Spoto and Lori M. Nichols contributed to this report.
Andy Polhamus may be reached at apolhamus@njadvancemedia.com. Follow him on Twitter @ajpolhamus. Find the South Jersey Times on Facebook.