New research reveals Yellowstone supervolcano's probable future eruption site

Live Science describes in its article that new research has provided insight into the future eruption patterns of the Yellowstone supervolcano. 

While an eruption is not expected anytime soon, future eruptions are anticipated to occur on the northeastern side of the national park, according to the study.

However, it's important to note that Yellowstone may not even remain a national park by the time an eruption happens, as any potential eruption is predicted to occur hundreds of thousands of years from now, explained Ninfa Bennington, a volcano seismologist at the Hawaiian Volcano Observatory, in an interview with Live Science.

The study, published on January 1 in Nature, revealed that rather than a single large reservoir, melted magma is stored in four distinct reservoirs within the caldera's crust.

To the west, the magma reservoirs are not in contact with the deep mantle rocks that would typically provide the necessary heat to keep the magma molten and ready to erupt. However, in the northeastern part of the caldera, near Sour Creek Dome, deep rocks are heating the magma trapped in the crust. As a result, while the magma on the western side of Yellowstone is likely to cool and solidify, the magma in the northeastern region will remain hot.

Earlier studies of Yellowstone attempted to determine the location of liquid magma versus solid rock by observing earthquake waves traveling through the caldera. However, the waves' behavior can be affected not only by the material's state but also by its temperature, making it challenging to distinguish between similarly heated solid rock and liquid magma.

The new study employed a technique called magnetotellurics to gain a clearer view. Earth's rotating core generates a magnetic field that surrounds the planet, and since magma contains magnetic minerals, pockets of molten magma create small magnetic fields that can be detected at the surface. Using instruments positioned around Yellowstone, researchers mapped these magnetic fields to locate the hidden magma pockets.

The study revealed that these four reservoirs together hold more liquid magma than was present during previous large, caldera-forming eruptions at Yellowstone. The magma is situated as deep as 6 or 7 miles (9.6 to 11.2 kilometers) beneath the surface. However, only in the northeastern part of the caldera does the magma come into contact with hot basalt rock from the mantle, which will keep it molten in the long term.

Although there is a significant amount of magma accumulating beneath Yellowstone, the caldera is not expected to erupt in the near future. This is because the magma is trapped in the pore spaces of solid rock within the caldera, similar to water being held in a sponge. According to Bennington, the magma can only become mobile and begin to erupt once more than 40 per cent of these pore spaces are filled. She and her team estimated that currently, less than 20 per cent of the pore spaces are filled, consistent with findings from other research.

"We have a much lower concentration of magma in these pore spaces, so a lot fewer of the pore spaces are filled with magma," she said. "What that means is you can’t interconnect these magmas to mobilize and erupt."

However, as hot rock gradually heats the northeastern magma reservoirs over tens of thousands of years, this situation could eventually shift. The precise timeline for this change, or whether it will occur before the mantle rocks in the northeastern part of Yellowstone lose contact with the magma reservoir, is still uncertain.

By Naila Huseynova