Magnetic Resonance Imaging of Multi-Phase Lava Flow Analogs: Velocity and Rheology

Janine Birnbaum, Wasif Zia, Alireza Bordbar, Ray F. Lee, Christopher M. Boyce, Einat Lev

Producción científica: Articlerevisión exhaustiva

1 Cita (Scopus)

Resumen

The rheology of lavas and magmas exerts a strong control on the dynamics and hazards posed by volcanic eruptions. Magmas and lavas are complex mixtures of silicate melt, suspended crystals, and gas bubbles. To improve the understanding of the dynamics and effective rheology of magmas and lavas, we performed dam-break flow experiments using suspensions of silicone oil, sesame seeds, and N2O bubbles. Experiments were run inside a magnetic resonance imaging (MRI) scanner to provide imaging of the flow interior. We varied the volume fraction of sesame seeds between 0 and 0.48, and of bubbles between 0 and 0.21. MRI phase-contrast velocimetry was used to measure liquid velocity. We fit an effective viscosity to the velocity data by approximating the stress using lubrication theory and the imaged shape of the free surface. In experiments with both particles and bubbles (three-phase suspensions), we observed shear banding in which particle-poor regions deform with a lower effective viscosity and dominate flow propagation speed. Our observations demonstrate the importance of considering variations in phase distributions within magmatic fluids and their implications on the dynamics of volcanic eruptions.

Idioma originalEnglish (US)
Número de artículoe2023JB026464
PublicaciónJournal of Geophysical Research: Solid Earth
Volumen128
N.º5
DOI
EstadoPublished - may 2023
Publicado de forma externa

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)

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