A 3D rendering of the Tamu Massif (Photo: Integrated Ocean Drilling Program)
It's been a banner month for striking geological discoveries. Last week, NASA scientists announced they'd found a canyon grander than the Grand Canyon hidden beneath an ice sheet in Greenland. Now, geologists have found the world's largest volcano, hiding in plain sight at the bottom of the Pacific Ocean.
The volcano, called the Tamu Massif, is 650 km wide and 4 km tall, covering a land area that far surpasses the previous record holder, Hawaii's Mauna Loa. Indeed, it's only about 25 per cent smaller than the solar system's biggest known volcano, Olympus Mons on Mars, lead researcher William Sager told LiveScience.
"We think this is a class of volcano that hasn't been recognized before," Sager said. "The slopes are very shallow. If you were standing on this thing, you would have a difficult time telling which way was downhill." The 4 km drop takes place very, very gradually: the slope near the summit is only one degree.
For a long time, scientists thought the Tamu Massif, located in the northwest Pacific, was merely part of a giant ocean plateau known as the Shatsky Rise. But after two decades of careful examination of lava samples and seismic surveys, the researchers were able to definitively classify it as a volcano — albeit one that hasn't errupted for about 144 million years.
Oh, and in case you're curious about the name: "Tamu" stands for Texas A&M University in College Station, Texas where Sager worked for 29 years (he recently decamped for the University of Houston).