List of unexplained sounds

The following is a list of sounds, where the source of the sound remains unknown:

Specific

• Bloop
• Colossi of Memnon
• Julia
• Quacker
• Slow Down
• Train
• Upsweep ('Upsweep' may have been tracked to an undersea South Pacific mountain that was not previously identified as "live",^[1] although this is still unconfirmed.^[2][3])
• Whistle

Non-specific

• The Hum
• Mistpouffers
• Unexplained booms

References