Two gigantic magma structures, including one fresh discovery, were spotted recently underneath Yellowstone National Park, right below the supervolcano whose last catastrophic eruption took place about 640,000 years ago.
Scientists from the University of Utah made use of seismic tomography to create a virtual facsimile of Yellowstone’s underground volcanic system. The larger magma chamber is located about 12 to 28 miles below the supervolcano, and is 4.4 times larger than the chamber previously discovered and known to researchers for the past several years. According to the researchers, the bigger magma reservoir is large enough to fill up the Grand Canyon several times over; reports are conflicted, but it’s estimated to be capable of doing this about 11 to 14 times. The first and smaller chamber can fill the Grand Canyon “only” 2.5 times.
“For the first time, we have imaged the continuous volcanic plumbing system under Yellowstone,” said researcher Hsin-Hua Huang in a statement. “That includes the upper crustal magma chamber we have seen previously plus a lower crustal magma reservoir that has never been imaged before and that connects the upper chamber to the Yellowstone hotspot plume below.”
Contrary to popular belief, the magma chamber and reservoir are not filled entirely with molten rock. Most of the rock is hot, solid, and sponge-like in texture, with small percentages of molten rock inside. The upper chamber, according to the study, is made up of 9 percent molten rock, while the lower part’s molten rock percentage is approximately 2 percent. Fortunately, however, it looks like neither structure is growing, and there is only a tiny (1 in 700,000) chance of another cataclysmic eruption in the near future.
“The magma chamber and reservoir are not getting any bigger than they have been, it’s just that we can see them better now using new techniques,” commented Huang’s co-researcher Jamie Farrell.