Bloop
Sound detected in 1997 from a non-tectonic cryoseism (ice quake)
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.
Sound profile
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. This is a stand-alone system designed and built by NOAA's Pacific Marine Environmental Laboratory (PMEL) to augment NOAA's use of the U.S. Navy Sound Surveillance System (SOSUS), which was equipment originally designed to detect Soviet submarines.
According to the NOAA description, 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 miles).
Ice quake origin
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 5,000 km (3,000 miles). This was found during the tracking of iceberg A53a as it disintegrated near South Georgia Island in early 2008. The iceberg(s) involved in generating the sound were most likely between Bransfield Strait and the Ross Sea; or possibly at Cape Adare, a well-known source of cryogenic signals.
Begin with the source’s own compact description: “Bloop” is sound detected in 1997 from a non-tectonic cryoseism (ice quake). The dossier treats that line as a proposition to test through Bloop, Sound and detected, not as a finished interpretation.
Why this record matters
The phrase “sound detected in 1997 from a non-tectonic cryoseism (ice quake)” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 11, 2026. The linked authority identifier is Q732267. Authority coordinates are -50.000, -100.000. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1997, 2012 and 2008.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
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This entry incorporates text from “Bloop” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.