The Bloop – An Underwater Mystery

The Bloop
In 1997, scientists were searching for underwater volcanoes off the coast of South America. That’s when they heard it – a strange, incredibly loud noise. Unsure of its origins, they simply called it the bloop.

The bloop was one of the loudest underwater sounds ever recorded. The noise was so intense, hydrophones, or underwater microphones, detected the same sound more than three thousand miles apart. What’s more, scientists initially had no idea what caused it.

Ships, whales, and other types of marine life all make sounds in the ocean. But for the bloop to be heard throughout the Pacific meant that scientists weren’t dealing with any old noise. They knew it had to be something unique.

Researchers suggest that up to 95% of the world’s oceans remain unexplored. When the National Oceanic and Atmospheric Administration, or NOAA, announced that the bloop wasn’t man-made, but rather an organic noise, various theories began to pop up.  

What massive animal could have created such a tune? Was it some undiscovered sea monster? An aquatic dinosaur that defied extinction? HP Lovecraft’s mythical beast, Cthulhu?

Obviously, there had to have been some sort of monstrous creature lurking deep in the ocean.

What Caused the Bloop?

For 15 years, debates on the origins of the bloop continued in the general public, but actual scientists had their own theories.

Scientists at NOAA surveyed acoustic data from the Bransfield Strait and Drake Passage from 2005 to 2010. When analyzing this data, it became pretty clear that ice breaking up and cracking is a common sound in the Southern Ocean. Scientists noted that the frequency and time-duration of the sounds produced by ‘icequakes’, as they are sometimes called, shared many characteristics with the bloop.

In 2012, NOAA concluded that the sound that produced the bloop was an icequake, and it turns out that is sort of what scientists always thought it was. Theories of giant sea creatures were more fantasy and imagination than science. As NOAA seismologist Robert Dziak states, “What has led to a lot of the misperception of the animal origin sound of the bloop is how the sound is played back. Typically, it is played at 16 times normal speed, which makes it sounds like an animal vocalisation of some sort. However, when the sound is played in real-time it has more of a ‘quake’ sound to it, similar to thunder.”

Ocean Noises

Even though the ocean can feel like a vast and mysterious place (which it is), most sounds picked up by NOAA hydrophones can easily be classified into different categories:

Geophysical – Submarine volcanoes, earthquakes.
Weather – Storms, waves, wind.
Anthropogenic – Ships, weapons.
Ice – Sea ice, iceberg groundings.
Animals – Cetaceans, fish.

Other sounds are usually just attributed to some kind of electronic interference with the signal.

Still, it is pretty easy to understand how the bloop could become such a fascinating story. Scientists have discovered unknown species of animals before. Remember, it wasn’t until 2004 that the first images of a live giant squid in its natural habitat were recorded.

With so much of the deep ocean yet to be explored, perhaps there really is an unknown species of giant sea creature prowling in deep ocean trenches. We’re coming for you Cthulhu.

Mark Heald

Mark Heald is an Associate Product Manager and Sporcle Admin. He enjoys spending time with his family, traveling, and bemoaning the fact the Sonics left Seattle.

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Mark Heald
About Mark Heald 152 Articles
Mark Heald is an Associate Product Manager and Sporcle Admin. He enjoys spending time with his family, traveling, and bemoaning the fact the Sonics left Seattle.