BrainStuff Classics: What on Earth Are Skyquakes?

There are plenty of potential reasons for a boom to rumble through the air, but skyquakes don't seem to be attached to any of the usual suspects. Learn more about these mysterious phenomena on BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, I'm Lauren Vogel Bam, and this is another
classic episode from our archives. In this one, we explore
the sometimes unsettling and still unexplained phenomenon of skyquakes. Hi
brain Stuff, Lauren Bogel bom Here. One November afternoon, in

(00:26):
residents of fifteen Alabama counties were reportedly startled by a
loud boom that caused some to call nine one one
operators in alarm. As the National Weather Services Birmingham station
tweeted not quite a couple hours later, there wasn't any
clear explanation for the noise. Radar scans and satellite imagery
of the region didn't show any large fires or smoke
from an explosion, and the U S Geological Survey didn't

(00:48):
spot any signs of an earthquake on its seismic monitoring system.
In their tweet, the National Weather Service speculated that the
sound may have been caused by an aircraft or meteor,
but said we don't have an answer and we canly
hypothesized with you. A NASA scientist soon knocked down those
possible explanations. Bill Cook, head of these space agencies, Meteoroid
Environment Office at the Marshall Space Flight Center in Huntsville, Alabama,

(01:12):
told al dot com that he was skeptical that the
sound could have been caused by a meteor because there
were no reports of anyone seeing a fireball. Cook also
discounted the possibility that the boom had been created by
an aircraft, noting that the seismic signature is not characteristic
of that produced by supersonic jets. Boom. About six hundred
miles or nine seven kilometers to the north in Ontario, Canada,

(01:34):
the Elgin Field infrasound array picked up an infrasound wave
that apparently was linked to the boom. It usually takes
something pretty big, such as a severe storm and avalanche
or rocket launch to trigger such a wave. To add
to the weirdness. Less than two weeks later, another similarly
unexplained boom was heard one morning in the Birmingham area.
We spoke with James Cooker, director of the Jefferson County,

(01:56):
Alabama Emergency Management Agency, via email. He said that he
heard a double boom, although the sound I heard may
have included an echo caused by the mountains, he said,
and Alabama isn't the only place where things have been
booming lately. Skyquakes, as they're commonly called, recently have been
heard across the US in states ranging from New Jersey
to Idaho, as well as in places as far away

(02:18):
as India, where two seaside resort towns were jolted in
August by a boom so loud that it shattered hotel windows,
according to the Dacca Tribune. Indeed, as u S Geological
Survey Scientist Emeritus David Hill detailed in a article on
the subject, mysterious booms have been heard for many years
in places across the world. In Belgium, they're known as
MIAs poofer's, while the Italians call them bron titi. In

(02:41):
the vicinity of Lake Seneca and the Catskill Mountains of
New York, residents have long heard the Seneca guns, a
phenomenon that was described by author James Fenimore Cooper back
in eighteen fifty one as a sound resembling the explosion
of a heavy piece of artillery that can be accounted
for by none of the known laws of nature. As
Hill noted in his article, numerous explanations for skyquakes have

(03:03):
been proposed over the years, including shallow earthquakes that could
produce audible sounds without noticeable shaking, massive tsunami waves breaking
far from shore, explosions of methane gas released from the
methyl hydrate beds sand dunes shared by avalanches, and of course, meteors.
As Hill wrote, meteors penetrating the upper atmosphere could create
sonic waves that wouldn't reach Earth's surface until after the

(03:25):
meteor had vanished, so the connection between the two wouldn't
be apparent. People have also raised the possibility that the booms,
or at least some of them, might be caused by
tests a secret U S military aircraft, such as the
long rumored spy plane that aircraft buffs have dubbed Aurora. However,
there may not be one single explanation for all the booms.

(03:45):
Hill explains it is indeed the case that there may
be several plausible explanations for any given incidents of a
mysterious booming sound, and that the environment where the sound
is heard will determine which of the possible explanations are
the most reasonable. A sound heard in the middle of
the desert, for example, is not likely due to breaking surf.
Hill says that most booming sounds are heard over a

(04:05):
limited range, so reports of clusters of booming sounds separated
by large distances are most likely coming from multiple sources.
The exceptions, he says, may include the sound from a
meteorite exploding in the atmosphere high above the earth, a
massive volcanic eruption, or an aircraft flying it's supersonic speeds
for an extended distance. Today's episode was written by Patrick J.

(04:32):
Kiger and produced by Tristan McNeil and Tyler Klang. For
more on this and lots of other topics, visit how
stuffworks dot com. Brain Stuff is production of iHeart Radio
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