An area the size of Chicago in Yellowstone National Park has been inflating and deflating by several inches over the past decade
The Norris Geyser Basin, the oldest, hottest and most dynamic thermal area in the park, was observed to rise 5.9 inches each year from 2013 to 2015 – an unusual event that left researchers baffled.
Now, using satellite radar and GPS data, experts have determined the ground deformation was caused by magma intrusions trapped below the basin’s surface.
As magma made its way to the surface, the pressure pushed rocks above it up and created an erratic pulsating effect, according to National Geographic.
This is the first time the scientific community has been able to track an entire episode of magma intrusion, which they say is a common occurrence throughout Yellowstone.
Yellowstone National Park sits in the northwest region of Wyoming and is home to bursting geysers, steam vents and bubbling pools.
At 3,472 square miles, the park is larger than the states of Rhode Island and Delaware combined. The uplift at Norris Geyser first began in 1996, but came to halt between 2013 and 2014 after a magnitude 4.9 earthquake struck the area.
Following the natural event, the ground started to sink back to its natural depth. However, data shows that the rise began again in 2016 and continued two years after – researches believe it has paused for now.
Dan Dzurisin, one of the study authors, wrote in the study: ‘Modeling…suggests the 1996–2004 uplift was caused by an intrusion of magma about 14 km [8.7 miles] beneath Norris.’
‘When magma intrudes the crust it cools, crystallizes, and releases gases that had been dissolved in the melt.
‘Gas escape lowers pressure in the magma, causing the surface to subside… But rising gases can become trapped under an impermeable layer of rock, causing the kind of rapid uplift seen at Norris from late 2013 until the 4.9 earthquake in March 2014.’
‘It seems likely the quake created microfractures that allowed gases to escape upward again, resulting in subsidence that ended in 2015.
‘The third uplift episode from 2016 to 2018 suggests rising gases became trapped again, this time at a slightly shallower depth.’
Dzurisin also noted in the study that this type of activity is common throughout the park and does not send off any alarm bells, Newsweek reported.
‘For the first time, we’ve been able to track an entire episode of magma intrusion, degassing, and gas ascent to the near-surface. For those in the know, like you, that’s awesome—not alarming,’ he explained.