List of unexplained sounds
The following is a list of sounds, where the source of the sound remains unknown:
The following unidentified sounds were detected by the USA National Oceanic and Atmospheric Administration using its Equatorial Pacific Ocean autonomous hydrophone array.
- Upsweep ('Upsweep' may have been tracked to an undersea South Pacific mountain that was not previously identified as a "live" volcano, although this is still unconfirmed.)
- Whistle ('Whistle' was only detected by a single autonomous hydrophone from the array.)
Formerly unidentified 
- Bloop The NOAA identified the sound as "consistent with icequakes generated by large icebergs as they crack and fracture".
- Julia The NOAA reports that "The most likely source of the sound formerly known as “Julia” is a large iceberg that has run aground off Antarctica."
- Slow Down The NOAA reported that "it is highly probable that this sound was produced by a large iceberg as it became grounded."
- Train The NOAA wrote that the sound "was most likely generated by a very large iceberg grounded in the Ross Sea, near Cape Adare." 
- Colossi of Memnon
- Quacker a sound claimed to have been reported by USSR submarines.
See also 
- "Tuning in to a deep sea monster". CNN. June 13, 2002. Retrieved 17 September 2011.
- "Acoustics Monitoring Program - Upsweep". PMEL.noaa.gov. Retrieved 2012-06-17.
- "Unidentified Sounds". www.pmel.noaa.gov. 2002-06-13. Retrieved 2011-05-08.
- "Acoustics Monitoring Program - Whistle". PMEL.noaa.gov. Retrieved 2012-06-18.
- "Icequakes (Bloop)". PMEL.noaa.gov. Retrieved 2012-11-26.
- "Iceberg Grounding on Seafloor (Julia)". Pacific Marine Environment Laboratory. PMEL.noaa.gov. Retrieved 2012-11-26.
- "Iceberg Grounding on Seafloor (Slow Down)". Pacific Marine Environment Laboratory. PMEL.noaa.gov. Retrieved 2012-11-26.
- "Acoustics Monitoring Program - Train". Pacific Marine Environment Laboratory. PMEL.noaa.gov. Retrieved 2012-11-26.
- Rob McCauley, John Bannister, Chris Burton, Curt Jenner, Susan Rennie, Chandra Salgado Kent (October 2004). Western Australian Exercise Area Blue Whale Project, Final Summary Report, Milestone 6 (Report). Australian Defence. http://www.cwr.org.au/wp-content/uploads/waxa2004.pdf. Retrieved 2012-06-26. "A signal type widely heard by Navy submariners and known as the bioduck is common in the [Perth] Canyon during late July-Dec [1999-2004]. The seasonal timing of the bioduck is similar to other great whales which migrate up from Antarctic waters."