Yellowstone Park's Massive Underground Volcano is Bigger Than We Thought

Tuesday, October 29, 2013

Yellowstone Park's Massive Underground Volcano is Bigger Than We Thought

First Posted: Apr 18, 2013 04:07 PM EDT

When volcanoes erupt, silica-rich magma can burst through the Earth's crust, burning the surrounding area in a massive explosion. Now, it turns out that this magma can lurk in Earth's upper crust for hundreds of thousands of years without triggering an eruption. (Photo : Flickr/Don Graham)

Yellowstone has the world's largest collection of geysers, and it has the underground plumbing to prove it. Scientists have announced that the volcanic activity beneath the National Park's surface may be far bigger and better connected than once thought.

The National Park is home to hot springs, mudpots, fumaroles and geysers, so it's not surprising that it has quite a bit of volcanic activity under the ground. Known as a hotspot, a massive volume of molten magma is located beneath Yellowstone. This plume of superheated rock rises from Earth's mantle, punching through the continent's crust as North America has slowly drifted over it. The phenomenon has left a trail of calderas created by massive volcanic eruptions in its wake; the most recent occurred about 640,000 years ago.
Yellowstone is infamous for its potential for a "super eruption." When the Huckleberry Ridge eruption in Yellowstone occurred about 2 million years ago, it darkened the skies with ash from southern California to the Mississippi River. It was one of the largest eruptions to have occurred on our planet. Understanding the volcanic activity of this location is therefore crucial for predicting future eruptions.

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nature.com

Large magma reservoir gets bigger

But earthquakes, not eruptions, are Yellowstone's most serious geological risk.

Alexandra Witze

28 October 2013

The reservoir of molten rock underneath Yellowstone National Park in the United States is at least two and a half times larger than previously thought. Despite this, the scientists who came up with this latest estimate say that the highest risk in the iconic park is not a volcanic eruption but a huge earthquake.

Yellowstone is famous for having a ‘hot spot’ of molten rock that rises from deep within the planet, fuelling the park’s geysers and hot springs¹. Most of the magma resides in a partially molten blob a few kilometres beneath Earth’s surface.

New pictures of this plumbing system show that the reservoir is about 80 kilometres long and 20 kilometres wide, says Robert Smith, a geophysicist at the University of Utah in Salt Lake City. “I don’t know of any other magma body that’s been imaged that’s that big,” he says.

Smith reported the finding on 27 October at the annual meeting of the Geological Society of America in Denver, Colorado.

Yellowstone lies in the western United States, where the mountain states of Wyoming, Montana and Idaho converge. The heart of the park is a caldera — a giant collapsed pit left behind by the last of three huge volcanic eruptions in the past 2.1 million years.

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