Faculty of Science and Technology

Environmental Geosciences Theme Seminar

Eruptions of silica-rich rhyolitic magma are among the largest and most explosive on Earth, but we have very limited understanding of what controls them. This is because rhyolitic eruptions are very infrequent, with the last major event occurring in Alaska in 1912.

However, in May 2008 a powerful rhyolitic eruption from volcán Chaitén in southern Chile generated a 30 km-high plume that widely dispersed ash over Argentina and prompted the successful evacuation of a nearby town, despite only 24 hours of warning. Within days the style of the eruption dramatically changed to the gentle effusion of obsidian lava.

Professor Jon Castro, who has led much of the volcanological research at Chaitén, will give an overview of the 2008 event and the new insights it provides about the behaviour of rhyolitic eruptions.