James Gardner
University of Texas at Austin, TX·Earth & Environmental Science
Explosive volcanic eruptions are driven by gas bubbles growing in molten rock, and their deadliest product is the pyroclastic density current — a fast, ground-hugging cloud of hot gas and rock fragments that has caused about a third of all eruption deaths. Research here spans both ends of that chain: how bubbles form and grow inside magma to make an eruption explosive, and how the resulting currents behave once they race across real hills and valleys.
- Fields
Earth & Environmental Science
Physics
- Topics
pyroclastic density current
pyroclastic flow
Mount St. Helens
- Grants
- 2 known grants, through Jul 2029
What they work on
- Reconstruct the 1980 Mount St. Helens pyroclastic density current in four dimensions by mapping the orientations of trees it knocked down and combining them with closely timed eruption photographs from multiple vantage points.
- Test how flow velocity, density and temperature controlled the current's response to rugged topography by comparing computational flow models against the 4D field reconstruction.
- Constrain a unified formulation for bubble nucleation in magma, covering both homogeneous nucleation in pure melt and heterogeneous nucleation on surfaces, through targeted laboratory experiments on eruption-relevant compositions.
- Build a bubble growth model that captures the collective behavior of interacting bubble cohorts using shell models, with nucleation sites assigned stochastically through a three-dimensional melt volume as conditions evolve.
- Combine the nucleation and growth components into a single community model that predicts how magma properties change along eruption pathways and enables inferring conduit conditions from erupted products.
More about the research
Both projects pair laboratory or field evidence with numerical models, because the interiors of magma conduits and of pyroclastic currents cannot be observed directly.
Why it matters
Hazard maps and public warnings for volcanoes depend on knowing how far and how fast pyroclastic currents travel over real terrain, and on predicting whether an eruption will be explosive at all. Ash from large eruptions can contaminate water supplies and farm soils, cause respiratory problems, and in extreme cases alter global climate. Better models of bubble growth and of flow-topography interaction could improve forecasts of eruption style and sharpen the hazard information given to communities living near volcanoes, and the planned museum exhibit would carry that understanding to the public.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Jessica Larsen
University of Alaska Fairbanks, AK·Earth & Environmental Science
Estimate magma storage depths beneath Mt. Edgecumbe by combining experimental petrology and melt inclusion analyses of rock samples with InSAR satellite measurements of ground deformation.
Esteban Gazel
Cornell University, NY·Earth & Environmental Science
Reconstruct pre-eruptive magma conditions, volatile saturation and degassing pathways of basaltic Plinian eruptions using olivine-hosted melt inclusions, droplets of melt trapped during crystal growth.
Alison Graettinger
University of Missouri-Kansas City, MO·Earth & Environmental Science
Determine at what depths silica-rich and basaltic magmas build up beneath Askja and how often magma is refilled, using plagioclase and clinopyroxene mineral analyses and gabbro xenoliths, chunks of deep rock carried up by eruptions.
The school
University of Texas at Austin: 49 labs on PI Pages, $1.1B a year on research, 871 research doctorates a year.
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