Experts say new findings don’t necessarily increase the ‘Yellowstone hazard’ – despite claims it could be due a catastrophic eruption.
A team from the University of Utah said the findings were “astounding” when presenting the study to the American Geophysical Union Fall Meeting in San Francisco.
Scientists found the underground cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock, BBC News reported.
“We’ve been working there for a long time, and we’ve always thought it would be bigger… but this finding is astounding.” Prof Bob Smith, from the University of Utah told the BBC.
When Yellowstone last erupted about 640,000 years ago a cloud of ash covered the whole of North America, affecting the climate.
But if the enlarged volcano were to erupt today, the consequences would be devastating for the whole world.
All the material that is shot up into the atmosphere [during an eruption] would eventually circle the Earth and affect the climate,’ Dr James Farrell, from the University of Utah, said.
The closest scientists can come to predicting the effect of an eruption is estimating that previous examples were 2,000 times more powerful than the one in Mount St Helens in 1980.
The extent of the molten lava brewing under the national park, which covers parts of Wyoming, Montana and Idaho, was discovered by recording seismic activity caused by the active volcano.
By measuring seismic waves as they travel through the ground, scientists were able to plot the course of lava.
‘The waves travel slower through hot and partially molten material … with this, we can measure what’s beneath,’ Dr Farrell explained.
The team’s findings, which were presented at the American Geophysical Union meeting in San Francisco, also found that the lava chamber reached further into the northeast of the park than previously thought.
While no one is sure when the active volcano will next burst back into life, Professor Smith said their findings didn’t make ‘the Yellowstone hazard greater’.
Some have predicted that an eruption is imminent and will occur every 700,000 years but the scientist said these figures were based on only three known eruptions, which happened 2.1 million years ago, 1.3 million years ago and 640,000 years ago.
The national park has also said that scientists would have plenty of warning that the volcano was warming up to something big, as earthquake activity and other indicators would increase.