According to the description provided by the NOAA, it had rised rapidly in frequence for about one minute, and was able to be heard at over 5,000m.
Dr. Christopher Fox of NOAA has said he does not believe its origin is man-made. Although the sound resembles a living creature, the sound is several times louder than the blue whale, which is the loudest recorded animal.
Fox then later stated that the Bloop could be ice calving in Antarctica. A year later, a journalist called David Wolman, made her own opinion on the origins of the sound:
"Fox's hunch is that the sound nicknamed Bloop is the most likely to come from some sort of animal, because its signature is a rapid variation in frequency similar to that of sounds known to be made by marine beasts. There's one crucial difference, however: in 1997 Bloop was detected by sensors up to 4800 kilometres apart. That means it must be far louder than any whale noise, or any other animal noise for that matter. Is it even remotely possible that some creature bigger than any whale is lurking in the ocean depths? Or, perhaps more likely, something that is much more efficient at making sound?
— David Wolman"
Many people interested in the bloop have stated that they believe the origin of the sound to be related to Lovecraft's work.
Below is a video about the bloop.