Episodic degassing from unsteady lava lake convection in Ray Lava Lake, Mount Erebus, Antarctica
Abstract/Contents
- Abstract
- Lava lakes are surface features that represent the upper portion of volcanic systems, and their behavior places limits on processes occurring in the interior of volcanoes. Persistently active lava lakes show continuous degassing and open convection over years to decades, which implies near steady-state conditions. The persistently active lava lake on Mount Erebus, Ross Island, Antarctica, known as Ray Lake, shows periodic activity in the form of small pulses of gas and hot magma at the surface every 5-18 minutes and occasional Strombolian eruptions while maintaining long-term near steady-state behavior in temperature, heat flux, gas flux, and composition when time-averaged over multiple cycles. This episodicity has been most commonly attributed to gas slugs: large gas bubbles rising through the conduit that burst at the surface. Alternate hypotheses, however, include unstable bidirectional flow in which episodicity is driven from the upper portion of the conduit. These hypotheses invoke a conduit source for episodicity. We present numerical simulations of Ray Lake with a constant inflow rate of gas-rich magma from the conduit and consider periodicity present in the convective pattern of the lava lake, consistent with a near-surface cause of episodicity. Our simulations of convection on Mount Erebus show drip instabilities with a periodicity of 5-20 minutes. Our results match the observed behavior well, showing a similar period as field observations. An increase in ascent velocity when magma enters the openly convecting lake can result in periodic behavior without invoking conduit dynamics, challenging existing ideas about near-surface volcanic conduit processes in persistently degassing volcanoes.
Description
| Type of resource | text |
|---|---|
| Date created | May 29, 2018 |
Creators/Contributors
| Author | Birnbaum, Janine |
|---|---|
| Primary advisor | Suckale, Jenny |
| Advisor | Keller, Tobias |
| Degree granting institution | Stanford University, Department of Geophysics |
Subjects
| Subject | School of Earth Energy & Environmental Sciences |
|---|---|
| Subject | Lava Lakes |
| Subject | Magma |
| Subject | Convection |
| Genre | Thesis |
Bibliographic information
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- User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Preferred citation
- Preferred Citation
- Birnbaum, Janine. (2018). Episodic degassing from unsteady lava lake convection in Ray Lava Lake, Mount Erebus, Antarctica. Stanford Digital Repository. Available at: https://purl.stanford.edu/ks996xx9045
Collection
Undergraduate Honors Theses, Doerr School of Sustainability
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- Contact
- janineb@ldeo.columbia.edu
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