MICHAEL MANGA: Recent Refereed Publications
Manga, M. (1996) Waves of bubbles in magmatic systems,
Journal of Geophysical Research, vol. 101, 17,457-17,466.
Initially homogeneous suspensions of bubbles in
basaltic magmas and lava flows
may become unstable and form rising waves or layers of
bubbles. We derive a set of model equations for the two-phase
(bubble-liquid) system and present the results of
a linear stability analysis and numerical simulations.
Periodic vesicle layers are preserved in Columbia River flows
with a spacing of ~1 m;
the prediction of the stability
analysis combined with a simple model for solidification of the lava
suggests that vesicle layers may represent waves of bubbles formed
within the flow.
The spacing of layers is determined by a balance between
the growth of bubbles and hydrodynamic self-diffusion.
Vesicular layers preserved in Columbia River flows may thus form
by hydrodynamic processes and do not require the repeated
injection of fresh volatile-rich magma or a periodic nucleation
Waves of bubbles may also develop in
magma chambers and conduits and could play a role in eruption dynamics.
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