Specific

• Bloop
  Bloop
  The Bloop is the name given to an ultra-low frequency and extremely powerful underwater sound detected by the U.S. National Oceanic and Atmospheric Administration in 1997...
  
  
• Colossi of Memnon
• Julia
  Julia (unidentified sound)
  "Julia" is a sound recorded on March 1, 1999 by the U.S. National Oceanic and Atmospheric Administration . NOAA said the source of the sound was unknown, but sufficiently loud to be heard over the entire Equatorial Pacific Ocean autonomous hydrophone array. It lasted for about 15 seconds, and its...
  
  
• Quacker
  Quacker (sound)
  Quackers are mysterious sounds, similar to a frog noise, widely reported by the crews of Soviet Navy submarines from various parts of the North Atlantic and Arctic Oceans during the peak of the Cold War, as well as their assumed sources...
  
  
• Slow Down
  Slow Down (unidentified sound)
  Slow Down is a sound recorded on May 19, 1997, in the Equatorial Pacific Ocean by the U.S. National Oceanic and Atmospheric Administration. The source of the sound remains unknown.-Analysis:...
  
  
• Train
  Train (unidentified sound)
  The Train is the name given to an unidentified sound recorded on March 5, 1997 on the Equatorial Pacific Ocean autonomous hydrophone array. The sound rises to a quasi-steady frequency...
  
  
• Upsweep
  Upsweep (unidentified sound)
  Upsweep is an unidentified sound detected on NOAA's equatorial autonomous hydrophone arrays. This sound was present when PMEL began recording SOSUS in August, 1991. It consists of a long train of narrow-band upsweeping sounds of several seconds duration each...
  
   ('Upsweep' may have been tracked to an undersea South Pacific mountain that was not previously identified as "live", although this is still unconfirmed.
• Whistle
  Whistle (unidentified sound)
  The Whistle is an unidentified sound recorded by the autonomous hydrophone deployed at a location in the Pacific Ocean with coordinates. It was recorded on July 7, 1997. Origin of the signal is unknown, and it was not detected on any other hydrophone...