Brontides, deep booming noises without any defined source, are audio cryptids. Have you heard one?
Some people call them Barisal Guns, because they are often heard in Barisal, near the Bay of Bengal. New Yorkers also hear them, although they call them Guns of Seneca, after Seneca Lake. Other people call them mistpouffers, or fog guns, when they boom in misty areas.
Brontides are characterized by their deep percusive sounds, and the fact that they always sound very far away. People all over the world report hearing these things, but a conclusive answer as to what they are has never been reached. Water is a common factor, and many speculate that it's tides of the sea, or wakes in a lake, hitting very resonant hollows at very lucky angles. Others think it's explosions of natural gas, or thunder. Some people even think that brontides are audible geological shifts, like earthquakes. Could even be UFOs.
Still others think that brontides are the cobbled-together products of a world that makes a lot of noise and a number of people's imaginations. They could be fireworks, planes passing overhead, traffic noise, or machinery working. During hunting season they could be gunfire. Since there's not a lot of money to be made from vague, loud booming sounds, it doesn't look like there will be any conclusive answer coming so - have any of you heard brontides? When, where, and how often?