December 17, 2013
Yellowstone’s Volcanic Caldera Much More Super Than Estimated
[ Watch the Video: Yellowstone Volcano Bigger Than Estimated ]
Lee Rannals for redOrbit.com - Your Universe Online
The new study finds the supervolcano is about 2.5 times bigger than earlier estimates, stretching for more than 55 miles.
Researchers used a network of seismometers situated around the national park to map out the magma chambers of the volcano. This method helped the team determine that the Yellowstone supervolcano contains 125 to 375 cubic miles of molten rock.
“We’ve been working there for a long time, and we’ve always thought it would be bigger, but this finding is astounding,” Professor Bob Smith, from the University of Utah, told the BBC's Rebecca Morelle.
The volcano’s chamber is 18 miles wide and runs at depths of three to nine miles below the Earth, meaning there is enough volcanic material below the surface to match the world's largest supervolcano's last three eruptions over the last 2.1 million years. The team said there has been nothing mapped of that size before.
Lead author Jamie Farrell of the University of Utah said the volcano’s largest blast was 2,000 times the size of the 1980 eruption of Mount St. Helens in Washington State. He said an eruption like this would spew large amounts of volcanic material into the atmosphere, where it would circle the Earth.
"It would be a global event," Farrell told The Associated Press. "There would be a lot of destruction and a lot of impacts around the globe."
The researchers record earthquakes in and around Yellowstone consistently, and they measure the seismic waves as they travel through the ground. These waves travel slower through hot and partially molten material, allowing the team to measure what lies beneath.
Smith said they are unsure of when another eruption will happen, and more data would need to be gathered before being able to make such a prediction. Scientists know there were major eruptions 2.1 million years ago, 1.3 million years ago and 640,000 years ago, but this isn’t enough data to make a solid prediction on when the next is coming.
“You can only use the time between eruptions (to work out the frequency), so in a sense you only have two numbers to get to that 700,000 year figure,” Smith told BBC. “How many people would buy something on the stock market on two days of stock data?”
Researchers from Brigham Young University in Utah said last week at the same meeting they have found evidence of a massive supervolcano on the border of Utah and Nevada. The team wrote in the journal Geosphere how this volcano erupted 30 million years ago with a power that was 5,000 times greater than the Mount St. Helens eruption.