Researchers at the University of South Hampton claim to have discovered the mechanism that triggers volcanic explosions. They say it is the pre-eruptive mixing of cooler magma and younger hotter magma that trigger powerful thunderstorms.
Researchers examined the crystal cumulate nodules found in pyroclastic deposits of large eruptions.
"The Las Cañadas volcanic caldera on Tenerife, in the Canary Islands, has generated at least eight major eruptions during the last 700,000 years," a statement on the university website read. "These catastrophic events have resulted in eruption columns of over 25km high and expelled widespread pyroclastic material over 130km. By comparison, even the smallest of these eruptions expelled over 25 times more material than the 2010 eruption of Eyjafjallajökull, Iceland."
The nodules trapped and preserved the final magma beneath the volcano immediately before eruption. Dr Rex Taylor, Senior Lecturer in Ocean and Earth Science at the University of Southampton, investigated nodules and their trapped magma to see what caused the eruptions. He found that the nodules provide a record of the changes occurring in the magma plumbing right through to the moment the volcano erupted.
"These nodules are special because they were ripped from the magma chamber before becoming completely solid - they were mushy, like balls of coarse wet sand," Dr. Rex said. "Rims of crystals in the nodules grew from a very different magma, indicating a major mixing event occurred immediately before eruption. Stirring young hot magma into older, cooler magma appears to be a common event before these explosive eruptions."
© 2025 HNGN, All rights reserved. Do not reproduce without permission.
