Skyquake

Skyquakes^[1] are unexplained reports that sound like a cannon or a sonic boom. They have been heard in several locations around the world such as the banks of the river Ganges in India, the East Coast and inland Finger Lakes of the United States, as well as areas of the North Sea, Japan and Italy.

Local names

Names (according to area) are:

• Bangladesh: Barisal Guns.^[2]
• Italy: "brontidi", "marine", "balza", "lagoni".^[3]
• Japan: "uminari"
• Netherlands and Belgium: "mistpoeffers"
• Philippines: "retumbos"
• United States: "Guns of the Seneca" around Seneca Lake & Cayuga Lake, Seneca guns in the Southeast US, and "Moodus noises" in lower Connecticut valley.
• elsewhere: "fog guns", "mistpouffers"

They have been reported from: on an Adriatic island in 1824; Western Australia, South Australia & Victoria in Australia; Belgium; frequently on calm summer days in the Bay of Fundy, Canada; Lough Neagh in Northern Ireland; Scotland; Passamaquoddy Bay, New Brunswick & Cedar Keys, Florida & Franklinville, New York in 1896 & in northern Georgia in the United States.^[4]

Their sound has been described as being like distant but inordinately loud thunder while no clouds are in the sky large enough to generate lightning. Those familiar with the sound of cannon fire say the sound is nearly identical. The booms occasionally cause shock waves that rattle plates. Early white settlers in North America were told by the native Haudenosaunee (Iroquois) that the booms were the sound of the Great Spirit continuing his work of shaping the earth.

The term originating in Seneca Lake, NY, mistpouffers, or Seneca Guns, referring to the rumble of artillery fire. An alternative explanation for the term "Seneca guns" is also provided. In 1850, James Fennimore Cooper, author of The Last of the Mohicans, wrote a story, “The Lake Gun,” describing the phenomenon as manifested on Seneca Lake of the upstate New York Finger Lakes, which seems to have popularized the term.

Hypotheses

One explanation for why they are usually heard near water is that inland communities are often too noisy to hear these booms. Their origin has not been positively identified. They have been explained as:

• Meteors entering the atmosphere causing sonic booms.
• Gas:
  • Gas escaping from vents in the Earth's surface.
  • With lakes, bio gas from decaying vegetation trapped beneath the lake bottoms suddenly bursting forth. This is plausible, since Cayuga Lake and Seneca Lake are two large and deep lakes.
  • Explosive release of less volatile gases generated as limestone decays in underwater caves.
• Military aircraft (though it cannot explain occurrences of the phenomenon which predate supersonic flight).
• In some cases, they have been associated with earthquakes.^[5] Earthquakes may not hold as a general cause because these sounds are often not accompanied by seismic activity, other than the vibrations induced by sound.^[6]
• In North Carolina, one speculation is that they are the sound of pieces of the continental shelf falling off into the Atlantic abyss. However, the Atlantic abyss is not only too far away from the east coast, but the Atlantic ridge is the result of very slow moving tectonics and couldn't produce such sounds given the frequency of their occurrence.^[7]
• A recent explanation is that the noise is very distant thunder which has been focused anomalously as it travelled through the upper atmosphere.^[8]
• Underwater caves collapsing, and the air rapidly rising to the surface.
• Firearms being discharged.
• Possible resonance from solar and/or earth magnetic activity inducing sounds.^[9]

See also

• Bell Island boom, attributed to a lightning superbolt
• List of meteor air bursts
• List of unexplained sounds
• Electrophonic hearing

References

External links

1. The Guns of Barisal and Anomalous Sound Propagation
2. www.astronomycafe.net
3. New Lands: A Hypertext Edition of Charles Hoy Fort's Book: Account of Barisal guns observed in 1874, and of some meteorite impacts
4. Account of Lake Guns - 1800's
5. Le son du Soleil fait résonner la Terre ! (French)
6. Les sons entendus aux 4 coins de la planète seraient-ils d’origine solaire? (French)
7. Sound and Light Phenomena: a Study of Historical and Modern Occurrences