Yellowstone is famous for its many hot springs, geysers and calderas, cauldron-esque volcanic features typically created when land collapses after a volcanic eruption. It’s also the site of what some geologists believe to be a super volcano. Each of these geothermic features occurs because a network of volcanic geography lies beneath the Earth’s crust in the Yellowstone vicinity. And that network was recently discovered to be considerably larger than previously estimated.
"We are getting a much better understanding of the volcanic system of Yellowstone," Jamie Farrell, a seismology graduate student at the University of Utah, told Fox News. "The magma reservoir is at least 50 percent larger than previously imaged."
The study reports that the magma reservoir beneath Yellowstone measures 37 miles long, 18 miles wide, and 3 to 7 miles deep. And all that magma is housed in a continuous underground network, not in individual pockets as believed before. The areas where the magma is closest to the Earth’s surface also match up to areas with the fiercest hydrothermal activity.
So how did the magma get there? Back in the days of shifting continents, the area of North America that we call Yellowstone settled on top of a geothermic hotspot. There, “the Yellowstone plume punched through the continent's crust, leaving a bread-crumb-like trail of calderas created by massive volcanic eruptions along Idaho's Snake River Plain, leading straight to Yellowstone,” reported Fox News.
The plume hasn’t caused trouble for a long time. The most recent small-scale eruption occurred 70,000 years ago, and a caldera hasn’t erupted for 640,000 years.
And thankfully, USGS geologist Jake Lowenstern, the scientist-in-charge of the Yellowstone Volcano Observatory, doesn’t think “the big one” is set to happen any time soon. “Calderas are big and hot, so they don't break very easily and they just move up and down. It's the way heat and gas get out of these deep systems — the system breathes," he told io9.com.