Carolina Beach resident Jody Smith was enjoying a Saturday morning with her son Roman when she felt and heard a 'boom.' Her son walked to her and asked, "Mommy, what was that?" Smith didn't know how to respond.
Many people in her neighborhood ran outside in hopes of finding the source of the noise.
"It feels like a Mack truck driving by and it just shakes your whole house," said neighbor Paula Powell.
"It's a shaking feeling," Smith added. "More than thunder and more than a truck going by. Initially that is what it sounded like but it turned into something more than that and I guess more movement. I went to Facebook and I asked, 'Did anyone else just feel a small earthquake?' And within minutes people were posting from all over town saying, 'I felt it in Mayfaire,' 'I felt it in Pine Valley.'"
Dozens posted on her wall and thousands have reported the noises up and down the coast on various websites from Georgia to Virginia. With speculative explanations ranging from the ordinary, like military aircraft to the outrageous like ghosts and aliens.
"I don't think it's ghosts, and I don't think it's aliens," said Geophysicist Dr. David Hill with the United States Geological Service in Menlo Park, California. "I think it's likely to be small earthquakes."
For nearly 50 years, Hill has studied just that across the globe, publishing more than 75 papers.
Hill said an earthquake produces audible sound by making the "ground around the person listening seem like they are in a big woofer."
"The ground is vibrating and that sound is transmitted up into the atmosphere and you hear a low rumbling sound," said Hill.
But on the east coast at the University of North Carolina Chapel Hill, another prominent Geophysicist says earthquakes have nothing to do with it.
"There are earthquakes occurring all around the world that we are recording here in North Carolina," said Dr. Johnathan Lees. "If we had a local earthquake it would be impossible for us not to record that."
Lees is also a life long student and teacher of sounds produced by the earth. The professor at UNC says of all the loud booms heard, recorded and studied there has never been any direct relationship discovered between any seismic activity.
"It's just very unlikely that we could have humans observe this and not have our very sensitive instruments making these observations," said Lees.
But Hill strongly disagrees saying, "Magnitude twos and smaller could produce an audible sound that and shaking that wouldn't be recorded on the seismic stations."
Lees thinks the sounds are something more secretive like military activity. There are a number of aircraft and submarine testing and bombing ranges off the coast stretching from Florida to New Jersey, with more than a dozen off the Carolina coastline. And supersonic flight can certainly make a boom.
But no military instillation is taking credit for the booms, and no exercises were scheduled at the time.
"We know that these things were reported long before people were flying around at the speed of sound," Hill pointed out.
In fact the term Seneca Guns, which is often used to describe these sounds comes from a James Fenimore Cooper story explaining the same phenomenon published in 1851, 50 years before man even learned to fly.
None the less, if it was an earthquake that rattled Smith's house there is no seismic evidence. Perhaps because of the lack of seismometers in the eastern half of the Carolinas.
"It just doesn't make sense how nothing could show up," said Smith as she plays with her son Roman. "How could nothing at all show up if all these people definitely felt and heard something that wasn't thunder that wasn't a plane and wasn't a truck driving by the house?"
Smith asks questions that even the most experienced scientists can't agree on an answer. Both Geophysicist, however, say you could eliminate some theories by installing a seismometer and sensitive microphones along the Carolina coastline.
But, since the booms do little more than rattle windows finding someone to foot the$10,000 to $20,000 bill in our current economy will likely keep the public guessing as to what is causing the mysterious booms.
Leaving folks like Smith to wonder and think, "it's just bizarre."