The “Bloop” emerged in the late 20th century as a mysterious underwater sound that captured significant public attention. Its unknown origin sparked widespread intrigue, raising questions about potential undiscovered ocean phenomena. This unique acoustic event became a subject of scientific curiosity and popular speculation.
The Mysterious Ocean Sound
The Bloop was an ultra-low-frequency, high-amplitude underwater sound first detected in 1997 by the U.S. National Oceanic and Atmospheric Administration (NOAA). It was picked up by the Equatorial Pacific autonomous hydrophone array, a system of underwater microphones designed to monitor undersea seismicity and detect Soviet submarines. The sound’s source was triangulated to a remote area in the South Pacific Ocean, around 50°S 100°W, west of the southern tip of South America.
The sound was powerful, heard on multiple sensors over 5,000 kilometers (about 3,000 miles) apart. Its duration was approximately one minute, and when sped up, it resembled a “bloop” sound, which gave it its name. The Bloop’s rapid variation in frequency initially led some to speculate about an unknown marine animal, as it was far louder than any known whale noise.
The Scientific Explanation
NOAA scientists investigated the Bloop, comparing its characteristics to known underwater sounds. They concluded the Bloop was not biological in origin, despite early speculation. The sound was determined to be an “icequake,” a seismic event caused by the fracturing of ice.
The Bloop’s acoustic profile matched sounds generated by large icebergs fracturing or calving from glaciers in Antarctica. Icequakes produce powerful, low-frequency sounds that propagate over vast distances through water, consistent with the Bloop’s wide detection range. Research by NOAA’s Pacific Marine Environmental Laboratory (PMEL) between 2005 and 2010, involving hydrophones closer to Antarctica, provided evidence supporting this explanation. The cracking of massive ice formations releases sound waves, explaining the Bloop’s volume and sonic signature.
Is There Any Danger?
Based on scientific understanding, the Bloop originated from an icequake and poses no direct danger to humans or vessels. It was the acoustic byproduct of a natural geological phenomenon: the breaking apart of large ice masses. While iceberg fracturing can be a powerful event, the sound waves generated are not inherently harmful.
Ice calving events, particularly those involving large ice masses, can potentially trigger localized tsunamis. However, the Bloop was the sound of such an event, not the physical impact itself. The resolution of the Bloop mystery confirmed it was a natural occurrence within the Earth’s dynamic cryosphere, not an unknown hazard.