A skyquake is a phenomenon where a loud banging sound is reported to originate from the sky. The sound may cause noticeable vibration in the ceiling or across a particular room. Those who experience skyquakes typically do not have a clear explanation for what caused them and they are perceived as mysterious. They have been heard in several locations around the world, several locations in the North Sea, the Ganges, Canada, Colombia, Japan, Finland, Australia, Italy, Ireland, India, The Netherlands, Norway, Tierra del Fuego in Argentina, the United Kingdom, the United States, Mexico, Malaysia (particularly Ipoh) and Indonesia (particularly Jakarta and Java).

Local names

Names (according to area) are: In 1804, they were reportedly heard during the Lewis and Clark Expedition near Great Falls. Meriwether Lewis wrote “since our arrival at the falls we have repeatedly witnessed a noise which proceeds from a direction a little to the N. of West as loud and resembling precisely the discharge of a piece of ordinance of 6 pounds at the distance of three miles.” William Clark added in his notes, “…a rumbling like Cannon at a great distance is heard to the west of us; the Cause we Can’t account.” They have been reported from an Adriatic island in 1824; Western Australia, South Australia and Victoria in Australia; Belgium; frequently on calm summer days in the Bay of Fundy and Passamaquoddy Bay, New Brunswick, Canada; Lough Neagh in Northern Ireland; Scotland; Cedar Keys, Florida; Franklinville, New York in 1896; and northern Georgia in the United States. 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 terms "mistpouffers" and "Seneca guns" both originate in Seneca Lake, New York, and refer to the rumble of artillery fire. James Fenimore Cooper, author of The Last of the Mohicans, wrote "The Lake Gun" in 1850, a short story describing the phenomenon heard at Seneca Lake, which seems to have popularized the terms.

Hypotheses

Their origin has not been positively identified. Given the long time that they have been known and reported, but with no proposal experimentally confirmed, it seems likely that they occur for more than one reason. Proposed explainations have been: