Giant Extinct Volcano Discovered In Pacific Ocean

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Justine Alford

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2020 Giant Extinct Volcano Discovered In Pacific Ocean
University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center. Read more:

Scientists scanning the unfathomed Pacific seafloor have discovered a gargantuan mountain lurking some 5,100 meters (16,700 ft) beneath the ocean surface.

The towering seamount rises 1,100 meters (3,600 ft) from the bottom of the ocean floor near the Johnson Atoll, 300 kilometers (186 miles) southeast of the uninhabited Jarvis Island.


Seamounts are undersea mountains forged by volcanic activity. They are generally extinct volcanoes found near tectonic plate boundaries, but they can also be found in the middle of plates at hotspot areas. While Everest may hold the record for the highest elevation on land, the tallest mountain in the world is actually a seamount. Hawaii’s Mauna Kea, a dormant volcano, is 10,200 meters (33,476 ft) tall when measured from base to peak; Everest is 8,850 meters (29,000 ft). Only 4,000 meters (13,100 ft) of Mauna Kea is above sea level, however.

The discovery was made by a team led by NOAA and University of New Hampshire scientist James Gardner. The researchers were using a 12-kHz multibeam echo sounder aboard a U.S. Navy oceanographic research ship to create detailed maps of the seafloor of this largely unexplored area. According to Gardner, they happened upon the seamount late at night on August 13, when it appeared completely “out of the blue” less than five days into their expedition. The researchers have since managed to map the conical mountain in its entirety.  

“These seamounts are very common, but we don’t know about them because most of the places that we go out and map have never been mapped before,” Gardner said in a news release. Furthermore, most of the existing maps of the seafloor have been generated using low-resolution satellite data which can’t pick up features like this, despite their size.

For now, the potential impact of this new discovery remains unclear. Seamounts are often biological hotspots that host an incredible array of marine life, but this one is far too deep to be able to provide rich fisheries. Furthermore, its depth means that it probably won’t be a navigational hazard for submarines.


“It’s probably 100 million years old,” said Gardner, “and it might have something in it we may be interested in 100 years from now.”

[Via UNH and Live Science]


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  • ocean,

  • seamount