Abstract
Basaltic eruptions are often characterized by cyclic changes of activity. At Hawaii, periods of continuous fountaining alternate with much longer periods of effusive outflow1,2. In Strombolian eruptions, activity proceeds through intermittent discrete bursts2–5. We report laboratory experiments that simulate the degassing process in basaltic eruptions. Gas bubbles are generated at the bottom of a tank filled with viscous liquid and topped by a small open conduit. The bubbles rise and accumulate at the roof in a foam layer whose thickness increases. At a critical thickness the bubbles coalesce and the foam collapses, generating gas pockets whose size depends on liquid viscosity and surface tension. At low viscosity a single large gas pocket is formed, which flows into the conduit. This erupts in an annular flow configuration where a central jet expels the liquid films that wet the conduit walls6. At higher viscosity many smaller pockets are formed, which rise as slugs and burst out intermittently at the vent. The experiments imply that the presence of constrictions in the chamber and conduits plays a major role in determining eruption behaviour.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
