In 1997, NOAA scientists recorded a strange, eerie sound deep in the South Pacific Ocean.
Theories about the origins of the sound included an unknown sea creature.
In 2011, NOAA scientists concluded that the sound was the cracking of an ice shelf during an earthquake.
In the summer of 1997, scientists recorded a strange, loud noise coming from an area west of Chile’s south coast. They dubbed it “the bloop.”
While searching for underwater volcanoes, researchers at the National Oceanic and Atmospheric Administration recorded the infamous loud, ultra-low-frequency sound on hydrophones. These underwater microphones originally developed by the US Navy were located 2,000 miles away in the Pacific Ocean.
The sound, which lasted for about a minute, was one of the loudest underwater sounds ever recorded. You can listen to the 16x sped up bloop below:
Paola Alexandra Rosa · Bloop, a mysterious sound from the depths of the ocean
Over the years, theories about the origin of the mysterious ocean sound abounded.
Some suspected it was the sound of military exercises, ships, a giant squid, blue whales or a new sea creature. After all, humans haven’t explored more than 80% of the world’s oceans.
“We considered every possibility, including animal origin,” Christopher Fox, chief scientist of NOAA’s Pacific Marine Environmental Lab’s Acoustic Monitoring Project, told The Atlantic for a short film about sound in 2017.
Just what created the booming noise has puzzled scientists for years.
It wasn’t until 2005, when NOAA undertook an acoustic survey of Antarctica off South America, that scientists began to understand the origins of the bloop.
Robert Dziak, of NOAA’s Pacific Marine Environmental Lab, told Insider by email that by 2011 — after gathering all the data — the agency was able to definitively explain what bloop was.
The official ruling: it was the sound of an earthquake, created by the breaking of an ice shelf as it broke away from an Antarctic glacier.
The “sound of cracking and cracking ice is a dominant source of natural sound in the Southern Ocean,” Dziak told Wired in 2012. sea ice and ice shedding from glaciers in the ocean, and these signals are very similar in character to the bloop”.
The icebergs that spawned the bloop most likely lay between Antarctica’s Bransfield Strait and the Ross Sea, or Cape Adare, according to NOAA.
Earthquakes occur when glaciers fracture in the ocean, breaking up the ice. The sudden pop produces a loud popping or rumbling sound. With climate change, NOAA warns that earthquakes are becoming more common.
Rising global temperatures melt glacial ice, creating water that can freeze again to cause an earthquake.
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