Move over, Mauna Loa Volcano: Earth’s largest volcano discovered and other volcano facts

Tamu Massif volcano

Tamu Massif volcano

For more than a century – since its first documented eruption in 1843 – Mauna Loa Volcano in the Hawaiian Islands has been considered Earth’s largest volcano. But although Mauna Loa makes up half of the big island of Hawai’i and rises 56,000 feet from base to summit, it just lost its title. The new champ, named Tamu Massif Volcano and located under the Pacific Ocean about halfway between the Hawaiian Islands and Japan, isn’t measured in thousands of feet: it’s 120,000 square miles. That’s about the size of New Mexico, or around the same size as the British Isles. Here are some details on the new discovery and some other fun volcano facts.


We know what they look like: towering mountains that spew ash and fiery lava. They’re the perfect fodder for disaster movies and tourist destinations – as long as they’re far enough away. But how is a volcano actually defined? According to the “Volcano” entry in The Columbia Encyclopedia, 6th Edition, available to readers free on Questia, volcanoes are “vents or fissures in the earth’s crust through which gases, molten rock or lava, and solid fragments are discharged.”

And you know what else?

  • Volcanoes are classified as active, dormant or extinct – but sleeping volcanoes can wake up more quickly than scientists had previously thought. Rather than 500 years, the former estimate, scientists determined in 2011 that dormant volcanoes might take only 20 to 80 days to become active.
  • More than 500 known volcanoes exist on Earth’s surface, but many more unknown volcanoes exist on the ocean floor.
  • The United States ranks third for volcanic eruptions, with a total of 50; Indonesia and Japan are in first and second place.
  • More than half of the world’s active volcanoes are located in the Pacific Ocean’s “ring of fire.”
  • The largest known volcano in the solar system is Mars’s Olympus Mons – but Tamu Massif is in the same league, and researcher William Sanger of University of Houston, who discovered the volcano, suggests that Tamu Massif may in fact rival Olympus Mons.

Tamu Massif

Named after Texas A&M University, where Sanger worked for almost three decades, Tamu Massif was originally thought to be three different structures underwater in the Shatsky Rise, more than 900 miles east of Japan. “We knew it was big,” Sanger was quoted as saying in the September 6, 2013, London Independent article “World’s largest volcano discovered off the coast of Japan,” by James Vincent. Sanger continued, “We had no idea it was one large volcano.”

Scientists had assumed that a structure of this size had to have been formed from several vents. But Sanger and his team discovered that Tamu Massif has only a single vent, marking the whole area as a single volcano.

Unlike both Mauna Loa and Olympus Mons, Tamu Massif’s size is primarily horizontal. Scientists have typed it a “shield volcano,” describing its shape close to the surface. “It’s not high, but very wide, so the flank slopes are very gradual,” Sanger was quoted as saying in the Independent. “In fact, if you were standing on its flank, you would have trouble telling which way is downhill.”

Why hasn’t it developed upward? Scientists suspect the lava is a very low viscosity, so as it flowed outward and hardened, other lava flow could happen underneath it, building layers below rather than above. It’s also a very heavy volcano, and Sanger theorizes that its weight has pushed it down into the Earth’s crust.

It’s not likely that scientists will get a new eruption from Tamu Massif to study it, however; the volcano has been dormant for around 140 million years.

Worst volcanic eruptions

While Tamu Massif might not make a disaster movie any time soon, there are plenty of active and dormant volcanoes that could be the stuff of action flicks. OurAmazingPlanet staffers for LiveScience posted “The 10 biggest volcanic eruptions in history,” including:

  • Krakatoa in Indonesia, whose massive explosion in 1883 also caused a killer tsunami
  • Santa Maria Volcano in Guatemala, which had one of the largest eruptions of the 20th century in 1902
  • Novarupta, Alaska Peninsula, whose 1912 eruption sent 3 cubic miles of magma and ash into the air
  • Mt. Thera, Island of Santorini, Greece, which exploded with the power of several hundred atomic bombs in 1610 B.C.E.
  • Mount Tambora, Sumbawa Island, Indonesia, which in 1815 had potentially the largest explosion ever recorded by humans

Need more to worry about? There’s also a supervolcano located under Yellowstone National Park. But the park assures people not to worry: another huge explosion from Yellowstone isn’t likely to occur for another 10,000 years.

Have you ever been to a volcano? Share your stories or links to your photos in the comments below.

Learn more about volcanoes by visiting Questia.

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