What are these mysterious booms heard around the world?
For years, folks around the world have reported loud, unexplained booms
Just about everyone has heard a strange boom in the distance. Many of these jarring noises have simple explanations, but others are a true curiosity.
These events are commonly dubbed “skyquakes,” and there’s still no complete explanation for what they are or why they occur.
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What was that boom?
Head over to your community’s page on social media and you’re sure to see at least one post asking “did anyone else hear that loud noise last night?”
Most loud noises are entirely explainable and utterly boring: dump trucks, fireworks, hunters, slamming doors.
Not every startle is so easy to write off. Folks around the world have reported so many loud booms that the phenomenon has different names in different regions, including skyquakes, mistpouffers, fog guns, and Seneca guns.
Several leads, but few conclusions
Unexplained booms occur in some areas more frequently than others.
Residents of coastal North Carolina hear skyquakes so often that a research team dove into the topic in 2020, ultimately falling short of finding a cause.
Folks across Alabama dubbed the phenomenon the “Bama boom.” For years, many people would report on social media that they heard house-rattling noises that seemingly came from nowhere.
“That was a thing around 2012 to 2017,” said James Spann, chief meteorologist for ABC 33/40 in Birmingham, Alabama. He noted that the reports “really slowed after 2018.”
When asked what he thought caused the Bama booms, Spann said that some of the likely sources included military jets and munitions at local bases, as well as kids playing with small explosives commonly used in target practice.
“Many are simply still a mystery,” Spann added.
Possible causes of some booms
What could cause some of these sudden sounds?
A loud bang can accompany cryoseisms, commonly called frost quakes. These can occur when very cold temperatures suddenly freeze water trapped within bedrock and cause the rock to break.
Some booms are almost certainly caused by munitions testing, firing ranges, and quarry blasting relatively close to populated areas.
A few experts speculate that the sounds are from bolides, or meteors that explode as they collide with Earth's thick atmosphere.
Closer to the surface, an atmospheric phenomenon called ducting is often responsible for otherwise unexplained booms, rumbles, and hums.
Ducting occurs when a temperature inversion just above the ground acts like a ceiling that reflects sound waves back toward the surface.
This creates an echoing effect that can stretch dozens of kilometres from the source of the sound, such as thunder, industrial activities, or heavy machinery.
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