Yellowstone supervolcano ‘even more colossal’ than previously thought

The supervolcano that lies beneath Yellowstone National Park in the US is far larger than was previously thought, scientists report.

A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.

A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.

The findings are being presented at the American Geophysical Union Fall Meeting in San Francisco.

Prof Bob Smith, from the University of Utah, said: “We’ve been working there for a long time, and we’ve always thought it would be bigger… but this finding is astounding.”

If the Yellowstone supervolcano were to blow today, the consequences would be catastrophic.

The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.

Now researchers believe they have a better idea of what lies beneath the ground.

The team used a network of seismometers that were situated around the park to map the magma chamber.

Dr Jamie Farrell, from the University of Utah, explained: “We record earthquakes in and around Yellowstone, and we measure the seismic waves as they travel through the ground.

“The waves travel slower through hot and partially molten material… with this, we can measure what’s beneath.”

The team found that the magma chamber was colossal. Reaching depths of between 2km and 15km (1 to 9 miles), the cavern was about 90km (55 miles) long and 30km (20 miles) wide.

It pushed further into the north east of the park than other studies had previously shown, holding a mixture of solid and molten rock.

“To our knowledge there has been nothing mapped of that size before,” added Dr Farrell. TRUNews