If the Yellowstone supervolcano was to erupt, we may get much shorter notice than experts thought, new research suggests.
Last time the volcano erupted, ash covered much of the country and blocked the sun for so long it caused a volcanic winter. It burst into the atmosphere with some 240 cubic miles of rock, dust, and volcanic ash—enough material to fill Lake Erie—twice.
While most would hope to never see it again, some scientists would settle for at least seeing it coming. Hannah Shamloo a graduate student and Christy Till, an assistant professor at Arizona State University, are such scientists.
In a quest to predict the next “big one,” they looked at the 631,000-year-old remnants of the last explosion.
Tuff Cliff in Yellowstone National Park. The different color on the cliff's face shows the layer of volcanic material from the previous massive explosion of the Yellowstone supervolcano. Jim Peaco/NPS
They found indices that caused them to dramatically reconsider how abruptly the volcano could reach a critical point.
The answers awaited them under the surface of tiny crystals of volcanic rock. The 1-2 millimeter crystals called phenocrysts formed layer by layer by cooling magma inside the volcano’s magma chamber. They were then hurled out during the eruption. Because magma composition changes with temperature, pressure, and water content, Shamloo and Till could look at the trace elements in different layers of the crystals to tell the conditions inside the magma chamber at different times—much like year-to-year changes in climate can be guessed from tree rings.
The Morning Glory hot spring in the Yellowstone National Park, Wyoming on June 2, 2011. Mark Ralston/AFP/Getty Images
They found that the crystals’ outermost layers, which formed right before the eruption, contained much more barium. That would suggest the eruption was caused by an injection of new magma from a deeper layer of the earth’s crust.
alh1/flickr, CC-BY-ND 4.0
Previously, scientists thought it would take thousands of years of geological changes to cause another eruption, giving people plenty of time to notice what’s in the works. Now it seems we could only have decades to prepare, given that scientists would detect the changes early.
Earlier this year the volcano shook with hundreds of small earthquakes. That, however, wasn’t enough to make scientists worry about any imminent threat of an explosion.
The volcano remains the most closely monitored one in the world and Shamloo and Till look forward to more research to expand and solidify their findings, which haven’t been peer-reviewed yet.
