The Bloop

The Definition

"The Bloop" was an ultra-low-frequency, high-amplitude underwater sound detected by the U.S. National Oceanic and Atmospheric Administration (NOAA) in 1997. For years, its mysterious nature and sheer volume fueled "junk" science theories about undiscovered sea monsters, until a more geological explanation was confirmed.

The Deep Dive

The sound was detected by hydrophones across the Pacific Ocean, originating from a remote point off the southern coast of Chile.

  • The Scale of the Sound: The Bloop was unique because it was picked up by sensors over 3,000 miles apart. To be heard at that distance, the sound had to be significantly louder than any known biological source. For context, the blue whale—the loudest animal on Earth—could not have produced a sound that traveled that far.

  • The "Cthulhu" Connection: Cryptid enthusiasts and internet theorists noticed that the coordinates of the sound were remarkably close to the fictional location of R'lyeh, the sunken city from H.P. Lovecraft’s The Call of Cthulhu. This led to years of speculation that a massive, unknown organism was lurking in deep ocean trenches.

  • The Glacial Reveal: In the early 2000's, NOAA deployed more sensitive sensors near Antarctica. They discovered that the acoustic profile of The Bloop perfectly matched that of an "icequake"—the sound of a massive iceberg cracking and breaking away from a glacier. When ice shelves fracture, they release a tremendous amount of energy that creates a low-frequency rumble that can travel across entire oceans.

  • Acoustic Ecology: The Bloop is a reminder of how the ocean acts as a massive conductor for sound. Because water is denser than air, sound waves—especially low-frequency ones—can travel for thousands of miles without losing their integrity, turning distant geological events into local mysteries.

Fast Facts

  • The "Julia" and "Train" Rivals: The Bloop wasn't alone. NOAA has recorded several other mysterious sounds with names like "Julia," "Slow Down," and "Train." Most of these have also been attributed to ice activity or seafloor volcanic movements.

  • Duration: The sound lasted for about one minute and featured a rapid frequency "upsweep," which is what gave it its organic, almost vocal name.

References

  • NOAA Pacific Marine Environmental Laboratory. (2012). The 'Bloop' Mystery Solved.

  • Ammer, C. (2013). The Dictionary of Clichés. Skyhorse Publishing.

  • Oxford English Dictionary. (2026). The Etymology of Hydroacoustic Phenomena.