Study advances understanding of volcanic eruptions

Volcanic eruptions vary from common, small eruptions that have little impact on humans and the environment to rare, large-to-gigantic eruptions so massive they can threaten civilizations. While scientists don't yet fully understand the mechanisms that control whether an eruption is large or small, they do know that eruptions are driven by the rapid expansion of bubbles formed from water and other volatile substances trapped in molten rock as it rises beneath a volcano. The mechanism is much the same as that involved in shaking a bottle of a carbonated drink and then opening the lid. Whether the volcano or the drink erupts dramatically or slowly loses its gas depends on the interplay of bubble growth and gas loss. Investigating the formation and growth of bubbles and their effects on magma properties thus provides a key to understanding volcanic eruptions, and could lead to better predictions of their scale. An international research team led by Prof. Don R. Baker of McGill University's Department of Earth and Planetary Sciences has published a new study in Nature that suggests the difference between a small or large eruption depends on the first 10 seconds of bubble growth in molten rocks. The findings point to a need to develop volcanic monitoring systems that can measure rapid changes in gas flux and composition during those brief, crucial moments.