Hidden beneath Yellowstone National Park is a supervolcano, capable of blasting over 1,000 cubic kilometres of rock and ash into the air, and plunging Earth into darkness.
While the supervolcano hasn’t erupted for 631,000 years, scientists have been working to understand what caused the last eruption.
Their findings suggest that the forces that lead to an eruption move much more rapidly than previously believed.
They claim new magma moves beneath Yellowstone only decades before a devastating eruption.
Previous estimates suggested that the geological process that leads to such an event takes millenniums to occur.
The researchers hope their findings will help to spot future supereruptions in the making.
Hidden beneath Yellowstone National Park is a supervolcano, capable of blasting over 1,000 cubic kilometres of rock and ash into the air. While the supervolcano hasn’t erupted for 631,000 years, scientists have been working to understand what caused the last eruption
Researchers at Arizona State University analysed rocks from Yellowstone’s Lava Creek Tuff – a fossilised deposit of ash from Yellowstone’s last supereruption.
Their study revealed trace crystals in the ash which contained details of temperature, pressure and water beneath the volcano.
Speaking to the New York Times, Dr Christy Till, an author of the study, said: ‘We expected that there might be processes happening over thousands of years preceding the eruption.’
But instead, the crystals revealed a rise in temperature and a change in composition that occurred on a rapid time scale.
This suggests that the last eruption occurred just decades after an injection of fresh magma beneath the volcano.
While the supervolcano hasn’t erupted for 631,000 years, scientists have been working to understand what caused the last eruption, in the hopes of anticipating the next (artist’s impression)
Ms Hannah Shamloo, lead author of the study, said: ‘It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption.’
The researchers hope their findings will help to anticipate future eruptions at Yellowstone.
The news comes just a week after it was revealed that an earthquake swarm at Yellowstone is now one of the biggest ever, with 2,475 tremors recorded since it began in in June.
Records show that 115 earthquakes were reported in the western part of the national park during September.
The largest swarm ever to occur at Yellowstone took place in 1985, with more than 3,000 events over a three month period.
Experts at the US Geological Survey (USGS) released the data as part of a monthly update.
Yellowstone National Park spans the midwestern US states of Wyoming, Idaho and Montana (pictured)
Of the 115 quakes, 78 were part of an ongoing swarm six miles north of West Yellowstone.
The biggest event in the swarm last month was magnitude 2.3, which occurred at 6.59pm Mountain Time (8.59pm ET / 1.59am Sep 4 BST).
Speaking to Newsweek Mike Poland, the scientist in charge at the USGS’s Yellowstone Volcano Observatory, said it is a ‘bit too soon’ to say whether the swarm has ended.
Records show that 115 earthquakes were reported in the western part of the national park during September. This graph uses GPS data to monitor rrends in ground displacement. Current deformation patterns at Yellowstone remain within historical norms
He said: ‘The activity has certainly waned drastically since August, and the swarm appears to be winding down, if not completely over.
‘It will probably take a little while longer to declare it “over”.’
The activity has spurred fears that the supervolcano could be gearing up to an eruption.
The precise number of earthquakes that have taken place is difficult to work out, because they can overlap or are too small to be recorded. This graph shows a time history of the Yellowstone caldera uplift and subsidence patterns, along with quarterly earthquake counts
But experts say the risk of such an event is low, and the alert level remains at ‘normal.’
If it were to erupt, the Yellowstone volcano would be one thousand times as powerful as the 1980 Mount St Helens eruption, although the risk is low.
‘Yellowstone hasn’t erupted for 70,000 years, so it’s going to take some impressive earthquakes and ground uplift to get these things started,’ the US Geological Survey explains.
‘Besides intense earthquake swarms (with many earthquakes above M4 or M5) we expect rapid and notable uplift around the caldera (possible tens of inches per year).
‘Finally, rising magma will cause explosions from the boiling-temperature geothermal reservoirs.
‘Even with explosions, earthquakes, and notable ground uplift, the most likely volcanic eruptions would be the type that would have minimal affect outside the park itself.’