Experts have been left baffled by a spate of seismic booms from Arizona to New York that appear to have gathered pace over the past week.
The string of phenomena was first reported last Thursday morning when locals in three separate Tennessee counties reported hearing loud booming noises.
On the same day, North Carolinians contacted police reporting unexplained loud blasts and booms that kept them awake at night.
Two homeowners said the booms were so powerful that they briefly lost power as a result of the tremors, Mysterious Universe reported.
Mary Buck told The Sun Online: “There was a loud boom heard in Gum Spring, Virginia, on Wednesday February 7 around 7pm.
“My neighbours and I heard it. We live close to interstate 64 so we just assumed something happened but there were no reported incidents.
“It sounded like an explosion. Could be related to other ‘mysterious boom’ noises reported?”
Similarly unexplained explosions have been reported happening in isolation over the past years, but rarely with this frequency.
On Saturday, loud bangs were reported in Rhode Island, where Jeremy Braza’s doorbell captured a video and audio of a loud noise over a three minute period.
The whole house shook. It woke my wife up, woke up all my childrenRhode Island Resident Jeremy Braza
“The whole house shook,” he told TurnTo10.com. “It woke my wife up, woke up all my children.”
The following night an explosion was heard in New York, accompanied by a mysterious flash in the sky.
“What the heck was that boom or explosion in park slope Brooklyn?”, asked Matt Wasowski on Twitter.
Another wrote: “Extremely loud boom in Brooklyn…..? Wtf??????”
Some speculated that the boom could have resulted from a manhole explosion, but the true origin is yet to be explained.
These booms were followed by “strange cannon-like sounds” in Harahan and River Ridge in Louisiana, where they have also kept residents up at night.
Residents say the sounds have been going on for weeks, and nobody seems to know what causes them.
While Philadelphians were rocked by a series of mystery booms a week ago, and again on Tuesday.
Mysterious Universe speculates that the phenomenon could be caused by cryoseisms or “frost quakes”, which could come about in extreme cold climates.