Much like a forensic team recreates a scene to determine how a crime was committed, UNH researchers are using scientific sleuthing to better understand the journey of magma, or molten rock, in one of Europe’s largest and most active volcanoes, Italy’s Mount Etna. Researchers combined three existing techniques to create a more accurate picture of the volcano’s ancient plumbing system and how quickly the magma rises to the top to cause an eruption. Their findings contribute to a broader understanding of how and when volcanoes erupt.
The study, led by UNH Earth sciences instructor Sarah Miller and recently published in the journal Geochemical Perspective Letters, set out to determine if the magma lingers below in pockets of the volcano or if it pushes up all at once. Miller and her team looked for chemical signatures in lava rock collected from flows on the surface and examined the elements making up minerals in these rocks to assess conditions under which the minerals crystallized.
As magma moves up through Earth’s crust beneath the volcano, it starts to crystallize. Some elements move rapidly and some more slowly, so there is a chemical record of events in those crystals that can help determine their journey. The researchers found a range of crystallization depths, suggesting there were discrete sites beneath the volcano where the rising magma crystallized.
The study yielded two interesting takeaways: First, the source that produced magma in the ancient Mount Etna is much the same as what happens in Mount Etna in the present-day. Second, the crystals were virtually chemically identical to the lavas in which they erupted, suggesting that the length of time for crystal storage beneath the volcano is likely relatively short. This finding may provide relevant insight on larger and more explosive eruptive systems, like the U.S.’s Yellowstone.