`Trigger` for explosive volcanic eruptions found

Washington: British scientists have identified a repeating underground trigger for the largest explosive volcanic eruptions on Earth.

Researchers from the University of Southampton have been studying the Las Canadas volcanic caldera on Tenerife in the Canary Islands, which has generated at least eight major eruptions during the last 700,000 years. These catastrophic events have resulted in eruption columns of over 25km high and expelled widespread pyroclastic material over 130km. By analysing crystal cumulate nodules (igneous rocks formed by the accumulation of crystals in magma) discovered in pyroclastic deposits of major eruptions, the scientists found that pre-eruptive mixing within the magma chamber – where older cooler magma mixed with younger hotter magma – appears to be the repeating trigger in large-scale eruptions. “Stirring young hot magma into older, cooler magma appears to be a common event before these explosive eruptions,” Dr Rex Taylor, Senior Lecturer in Ocean and Earth Science at the University of Southampton, said. The Las Cañadas volcano has been considered worthy of particular study in light of their history of large, destructive eruptions and proximity to populated area, the researchers said. (ANI) ANI