With its seething rivers, long canyons and lush forests, Yellowstone National Park is an absolute gem! But under the picturesque landscape is hidden real hell, which is just waiting to break out.
Using computer models, the researchers simulated conditions beneath the largest supervolcano in North America and discovered an area that could control the movement of magma flowing out of the Earth's mantle.
Although a huge reservoir of magma is hidden under Yellowstone National Park, it has been 630 thousand years since this hidden supervolcano survived a super-eruption, and 70 thousand years since the last major lava spill. Scientists do not know exactly when the next eruption will occur or if it will happen at all, but if it does, lava will pour out of the Yellowstone caldera and cover an area within a radius of 48-64 km.
New research, published this week in Geophysical Research Letters, improves our understanding of how magma reservoirs are located beneath Yellowstone National Park and how this vast lava system works. Using computer models, a team led by geologist Dylan Colon of the University of Oregon has discovered a previously unknown crustal transit zone that can tell us how magma deep below the surface crawls up and pours out onto the surface. The new study doesn't tell us when a new eruption will occur, but it definitely takes a step in that direction.
The thin layer of bark in Yellowstone is all that separates us from boiling evil. At times, the crust is heated and softened by magma, allowing the lava to flow out of a giant gap called the mantle jet. In 2014, researchers used seismic waves to find a huge reservoir of magma in the upper crust, but thanks to the huge volume of carbon dioxide and helium that leaked out of the earth, scientists figured out that there was even more magma deeper. This assumption was proven to be true in 2015, when scientists, also using seismic waves, found an even larger reservoir of magma at a depth of 20-45 km.
As important as these results are, they do not tell geologists about the composition, state, and amount of magma contained in these pockets. To fill the knowledge gap, Colon developed computer simulations that rely on this information to visualize what is happening beneath Yellowstone. In particular, the researchers tried to determine where magma is most likely to accumulate under the crust.
According to the model, opposing geological forces push against each other at a depth of 5-10 km. This creates a transition zone where cold stable rock gives way to hot, partially molten rock below. This transition zone, called the mid-crustal sill, traps the rising magma, causing it to accumulate and solidify over a large horizontal area.
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Models suggest that the sill is about 15 km thick. The simulation is tied to seismic data from 2014 and 2015, which suggests that the models are a reasonably accurate approximation of the real world.
The results also show that the sill is mainly composed of rock that formed from cooled magma, and that magma reservoirs exist both above and below it. Those above contain gas-laden rhyolite magma that periodically erupts to the surface.
Scientists don't know when Yellowstone will explode again, but we now have an explanation for the magma system that produces these eruptions. For example, we know where eruptive magma comes from and where it accumulates.
Similar processes can occur anywhere, and the task of scientists now is to compare these systems. We cannot predict eruptions, but such breakthroughs mean that eventually we will be able to achieve it.