In 1997, NOAA scientists recorded a terrifying, strange noise in the depths of the South Pacific Ocean.
Theories about the origin of the sound include an undiscovered sea creature.
In 2011, NOAA scientists concluded that the sound was the cracking of an ice shelf during an icequake.
In the summer of 1997, scientists recorded a strange, loud sound emanating from an area west of Chile’s southern coast. They called it “the bloop.”
While searching for underwater volcanoes, researchers from the National Oceanic and Atmospheric Administration recorded the infamously loud, ultra-low frequency sound on hydrophones. These underwater microphones that the US Navy originally developed were located 2,000 miles apart in the Pacific Ocean.
The sound, which lasted about a minute, was one of the loudest underwater noises ever recorded. You can listen to the bloop sped up 16 times below:
Paola Alexandra Rosa · Bloop, a mysterious sound from the deep ocean
Over the years, there have been theories about the origin of the mysterious ocean sound.
Some suspected it was the sound of military exercises, ships, a giant squid, blue whales or a new sea creature. After all, man has not explored more than 80% of the world’s oceans.
“We considered every possibility, including animal origin,” Christopher Fox, chief scientist for NOAA’s Pacific Marine Environmental Lab’s Acoustic Monitoring Project, told The Atlantic for a 2017 short film about the sound.
Exactly what caused the booming sound puzzled scientists for years.
It wasn’t until 2005, when NOAA began an acoustic survey of Antarctica off the coast of South America, that scientists began to understand the bloop’s origins.
Robert Dziak, of NOAA’s Pacific Marine Environmental Lab, told Insider via email that in 2011 — after collecting all the data — the agency was able to definitively explain what the bloop was.
The official verdict: It was the sound of an icequake, caused by the cracking of an ice shelf as it broke from an Antarctic glacier.
The “sound of breaking and cracking ice is a dominant source of natural noise in the southern ocean,” Dziak told Wired in 2012. sea ice and ice calving off glaciers into the ocean, and these signals are very similar to the bloop.”
The icebergs that caused the bloop were most likely located between Antarctica’s Bransfield Straits and the Ross Sea, or Cape Adare, according to NOAA.
Icequakes occur when glaciers in the ocean break and crack ice. The sudden creak produces a loud bang or booming sound. With climate change, NOAA warns that icequakes are becoming more common.
Rising global temperatures are causing glacial ice to melt, creating water that can refreeze and trigger an icequake.
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