Temperature and Water Content Cycles Within Magma Reservoirs Linked to Volcano Eruption Force

The researchers found that before the 2014 explosive eruption at Kelud, the magma was in a cool and water-rich state, whereas in 2007, before the less explosive lava dome eruption, the magma was hotter and dryer. “Even relatively small changes in the temperature and water content of the magma can drastically alter the chemical and physical properties of the unerupted magma,” explained lead author Dr. Mike Cassidy from the Institute of Geosciences at Mainz University. “For instance, when the temperature drops, this makes the magma stickier, which means the gas finds it harder to escape, thus building up pressure leading to an explosive eruption.”

The hotter and dryer magma conditions are attributed to the fresh input of water-poor magma from below, which mixes and thus dilutes the magma in water content. The study goes some way to explaining why volcanoes erupt in different ways and could in the future help to forecast how explosive an impending eruption will be.