An analogue experimental model of depth fluctuations in lava lakes

Witham, F. and Woods, A. W. and Gladstone, C. (2006) An analogue experimental model of depth fluctuations in lava lakes. Bulletin of Volcanology, 69. pp. 51-56. DOI 10.1007/s00445-006-0055-8

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Abstract

Lava lakes, consisting of molten degassing lava in summit craters of active basaltic volcanoes, sometimes exhibit complex cycles of filling and emptying on timescales of hours to weeks such as recorded at Pu’u’O’o in Hawaii and Oldoinyo Lengai in Tanzania. Here we report on a new series of analogue laboratory experiments of twophase flow in a reservoir-conduit-lava lake system which spontaneously generates oscillations in the depth of liquid within the lake. During the recharge phase, gas supplied from a subsurface reservoir of degassing magma drives liquid magma up the conduit, causing the lake to fill. As the magmastatic pressure in the lake increases, the upward supply of magma, driven by the gas bubbles, falls. Eventually the upflow becomes unstable, and liquid drains downwards from the lake, driven by the magmastatic pressure of the overlying lake, suppressing the ascent of any more bubbles from the chamber. At a later stage, once the lake has drained sufficiently, the descent speed of liquid through the conduit decreases below the ascent speed of the bubbles, and the recharge cycle resumes. Application of a quantitative model of the experiments to the natural system is broadly consistent with field data.

Item Type:	Article
Uncontrolled Keywords:	2006 AREP IA51 2006 P BPI
Subjects:	99 - Other 02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title:	Bulletin of Volcanology
Volume:	69
Page Range:	pp. 51-56
Identification Number:	10.1007/s00445-006-0055-8
Depositing User:	Sarah Humbert
Date Deposited:	16 Feb 2009 13:04
Last Modified:	23 Jul 2013 09:54
URI:	http://eprints.esc.cam.ac.uk/id/eprint/809

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