Crystal-gazing to predict eruptions

Tiny crystals produced deep inside volcanoes could potentially provide valuable information leading to better eruption predictions, researchers have found.

Teresa Ubide from the University of Queensland and Balz Kamber from Trinity College Dublin, in Ireland, have discovered that crystals of a mineral called clinopyroxene form when fresh magma rushes into a volcano’s chamber, catalysing a range of chemical reactions.

Such inrushes often trigger eruptions, sometimes on days later. Ubide and Balz discovered that the clinopyroxene crystals accumulate traces of chromium at different stages of the mixing process, effectively recording the history of their host volcano in the time leading up to an eruption.{%recommended 5821%}

To make their finding, the researchers examined clinopyroxene crystals ejected from Mt Etna in Italy during a spate of eruptions that occurred between 1974 and 2014.

They exposed the crystals to a process known laser ablation-inductively coupled plasma mass spectrometry (LAICPMS) to accurately measure chromium traces within them. They then coupled the data with that obtained from a process called thermobarometry, in which minerals found within volcanic rock can be used to trace its history of temperature and pressure changes.

Using these methods, they discovered that crystals could effectively be read as a record of Mt Etna’s pre-eruption periods.

The scientists say that further research is needed, particularly in order to better understand the growth rates of clinopyroxene. This, in turn, will likely lead to an improved understanding of magma behaviour, permitting, hopefully, more accurate eruption forecasting.

“This could signal good news for the almost one in 10 people around the world who live within 100km of an active volcano,” says Ubide.

“We haven’t yet reached the ‘holy grail’ of being able to predict volcanic eruptions, but our research is a significant step forward in understanding the processes that lead to eruption.”

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