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volcanic eruptions

An eruption chronometer

Supervolcano viewed from space: Gulf of Naples and sequence of craters of Campi Flegrei

ESA e Wikimedia commons Supervolcano viewed from space: Gulf of Naples and sequence of craters of Campi FlegreiESA e Wikimedia commons

An international research team including Brazilian vulcanologist Cristina De Campos has replicated in the laboratory what happens in the magma chamber of a volcano, where the molten rocks that form the different types of magma mix together before an eruption. The experiment enabled the researchers to more accurately measure the time it takes for a volcano to erupt or explode after its magma chamber fills and magma mixing begins. In the analyzed cases, it took less than an hour, instead of several days as once imagined (Scientific Reports, September 21, 2015). In the laboratories coordinated by Donald B. Dingwell at Ludwig-Maximilian University in Munich (Germany), De Campos heated two types of magma from the Campi Flegrei supervolcano in Naples (Italy) to temperatures near those found inside volcanoes, then measured the time necessary for them to chemically react and mix together. In nature, the decompression of this mixture liberates gases that expand the magma and eject it from the volcano. Based on this information, the researchers created a mathematical model that enabled them to estimate the time lapse between the start of magma mixing and eruption. Tests using material from three explosions at Campi Flegrei, the most dangerous volcano in Europe, indicated that this interval is less than an hour. “This type of information is important for civil defense, as once the volcano’s magma chamber is filled, it will erupt almost immediately,” says De Campos. She believes that the same estimate also applies to volcanoes of similar composition.