Steve Sparks on What Makes a Volcano Erupt
Steve Sparks at the Erciyes volcano, one of the largest active volcanoes in Turkey.
Steve Sparks is a Professor at the School of Earth Sciences at Bristol University. He has made major contributions to our understanding of how volcanic eruptions work by applying physics and fluid mechanics to the melted and solid material beneath volcanoes. In this work, he uses a combination of studies in the field, laboratory experiments, analytical studies and computer-based modelling.
Listen to the podcast here, or wherever you get your podcasts.
Scroll down for illustrations that support the podcast.
Note - playing the podcast is not supported on Internet Explorer; please use any other browser, or listen on Spotify, Apple Podcasts, etc.
Podcast Illustrations
Classical model of a volcano with a permanent shallow magma chamber.
Current model of a volcano in which melted material is stored between the crystals of an extensive mush. The melt separates out from the mush very slowly. Because it is lighter than the surrounding rock, it is unstable, and rises to the surface, with only transient storage in a shallow magma chamber.
Lab experiments show how an instability forms between liquids of different densities and viscosities. In this experiment, the denser, less viscous material (analogous to the melt) is placed above the denser more viscous material (analogous to the crustal rocks). This is upside down compared to the real world, in which the melt is produced below the rocks, and finds its way to the surface when an instability forms at the melt/rock boundary, causing a blob of melt to pinch off and rise.
All images courtesy of Steve Sparks