The Mysterious Bloop



9 Questions

What is Bloop?

What was the original speculation about the source of Bloop?

Where was the source of Bloop roughly triangulated to be?

What is the Equatorial Pacific Ocean autonomous hydrophone array primarily used for?

What was the NOAA Vents Program's attribution of Bloop's sound?

What is the process responsible for acoustical emissions similar to those from ice calving?

Why was the source of Bloop a mystery?

What is the current consensus about the source of Bloop's sound?

What is one similarity between numerous ice quakes and Bloop?


Mystery of Bloop: Underwater Sound Detected in 1997 from Non-Tectonic Cryoseism

  • Bloop was an ultra-low-frequency, high amplitude underwater sound detected by the U.S. National Oceanic and Atmospheric Administration (NOAA) in 1997.
  • The sound was originally speculated to have originated from a marine animal but was later described by NOAA as being consistent with noises generated via non-tectonic cryoseisms originating from glacial movements such as ice calving, or through seabed gouging by ice.
  • The sound's source was roughly triangulated to 50°S 100°W, a remote point in the south Pacific Ocean west of the southern tip of South America.
  • The sound was detected by the Equatorial Pacific Ocean autonomous hydrophone array, a system of hydrophones primarily used to monitor undersea seismicity, ice noise, and marine mammal population and migration.
  • The sound "rose" in frequency over about one minute and was of sufficient amplitude to be heard on multiple sensors, at a range of over 5,000 km (3,000 mi).
  • The NOAA Vents Program has attributed the sound to that of a large cryoseism (also known as an ice quake).
  • Numerous ice quakes share similar spectrograms with Bloop, as well as the amplitude necessary to detect them despite ranges exceeding 5000 km.
  • In ice calving, variations result from a sound source's own motion.
  • Two processes known as rubbing and ridging are responsible for acoustical emissions similar to those from ice calving.
  • The source was a mystery because it would be "far more powerful than the calls made by any animal on Earth."
  • Over the last decade consensus has supported the argument that the noise is produced by ice fracturing processes.
  • Bloop remains one of the most mysterious sounds ever recorded in the ocean.


Test your knowledge about the enigmatic Bloop sound, one of the most mysterious underwater sounds ever recorded. Discover the history of its discovery, its possible sources, and the scientific research conducted to unravel its mystery. Take this quiz and explore the fascinating world of underwater acoustics and cryoseismology.

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