Unidentified sounds

ancient Egyptian statues

thumb|A spectrogram of Bloop Bloop was an ultra low frequency, high-amplitude underwater sound detected by the U.S. National Oceanic and Atmospheric Administration (NOAA) in 1997. By 2012, earlier speculation that the sound originated from a marine animal was replaced by NOAA's description of the sound as being consistent with noises generated via non-tectonic cryoseisms originating from glacial movements such as ice calving, or through seabed gouging by ice.

acoustic phenomenon

A skyquake is a phenomenon where a loud sound is reported to originate from the sky. It often manifests as a banging, or a horn-like noise. The sound may cause noticeable effects on buildings, including vibration in ceilings or across the walls of 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, typically in areas close to lakes and other bodies of water. Reports of skyquakes have come from the North Sea, the Ganges, Canada, Colombia,

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