Determining rate of magma injection may lead to more reliable volcanic forecasting

By: Patrick Gillespie

Forecasting volcanic eruptions has been spotty at best due mostly to the inability to identify reliable eruptive precursors. But a group of researchers at Cornell University’s College of Engineering, Roma Tre University and the University of Leeds may have found a solution to that problem.

The research team addresses this limitation in a scientific article published today in Nature Geoscience, showing that a novel parameter, which can be indirectly measured at volcanoes, is a good indicator of whether it will go on to erupt or not.

“This precursor is the rate of magma injection within the volcano in the weeks to months before the eruption, derived from measurements of surface deformation from satellites,” said Federico Galetto, a postdoctural research associate in Cornell’s Department of Earth and Atmospheric Sciences. “The approach has been tested in some highly-active and frequently erupting type of volcanoes, those with calderas, which are wide volcanic depressions at the surface formed in the past by the partial emptying of the magma chamber below.”

In particular, Galetto says, the precursor has been tested at calderas that erupt a very common type of magma known as “basalt”.

Figure 1: Eruption vs. No EruptionForecasting eruptions is the main challenge for volcanology, as ultimately it can reduce the impact of volcanic activity on the population and environment. Volcanology has experienced some success in forecasting eruptions on short timescales of hours to days beforehand. Nevertheless, these timescales may be too short for appropriate mitigation measures, including the evacuation of the population, especially in densely populated areas.

“Ideally, volcanologists would issue reliable medium-term forecasting, on a timescale of weeks to months,” to give authorities the opportunity to implement appropriate prevention plans, said Galetto.

The results of the research show that it is possible to successfully forecast eruption for 86% of the cases, which is far higher than hit rates currently obtained through any other parameter. In particular, if the rate of magma injection below the caldera is high, eruption occurs within one year in all the considered cases; conversely, if the rate of magma injection is low, eruption does not occur for 86% of cases.

“This novel approach may also be applicable for other types of volcanoes, which would offer an exciting prospective in forecasting eruptions more generally,” Galetto said. “As the rate of magma injection can be estimated from satellites in near-real-time for most volcanoes in the world, regardless of their location and accessibility, this may allow a widespread, prompt and remarkably early warning—weeks to months in advance—a crucial support when densely inhabited areas may need to be evacuated.”

The research was published in Nature Geoscience on June 23 and the co-authors include Galetto, Valerio Acocella from Rome Tre University’s Department of Science, Andrew Hooper from the University of Leeds’ School of Earth and Environment and Marco Bagnardi, formerly from Leeds and now with NASA Goddard Space Flight Center; Greenbelt, MD.

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