Periodic sulphur dioxide degassing from the Soufrière Hills Volcano related to deep magma supply

Christopher, T. and Edmonds, M. and Taisne, B. and Odbert, H. and Costa, A. and Hards, V. and Wadge, G. (2014) Periodic sulphur dioxide degassing from the Soufrière Hills Volcano related to deep magma supply. In: The Role of Volatiles in the Genesis, Evolution and Eruption of Arc Magmas. Geological Society special publication, 410 (410). The Geological Society, London, SP410.11. ISBN 9781862396890

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Abstract

Soufrière Hills Volcano produced prodigious quantities of sulphur dioxide (SO2) gas throughout 1995–2013. An unprecedented, detailed record of SO2 flux shows that high SO2 fluxes were sustained through eruptive pauses and for two years after the end of lava extrusion and are decoupled from lava extrusion rates. Lava extrusion rates have exhibited strong 1- to 2-year cyclicity. Wavelet analysis demonstrates periodicities of c. 5 months and c. 2 years within the SO2 time series, as well as the shorter cycles identified previously. The latter period is similar to the wavelength of cycles in lava extrusion, albeit non-systematically offset. The periodicities are consistent with pressure changes accompanying deformation in a coupled magma reservoir system whereby double periodic behaviour may arise from limited connectivity between two reservoirs. During periods of lava extrusion SO2 is released together with the lava (yielding the c. 2 year period), albeit with some offset. In contrast, when magma cannot flow because of its yield strength, SO2 is released independently from lava (yielding the c. 5 month period). Our results have implications for eruption forecasting. It seems likely that, when deep supply of magma ceases, gas fluxes will cease to be periodic.

Item Type: Book Section
Uncontrolled Keywords: 2015AREP; IA68;
Subjects: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Divisions: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
08 - Green Open Access
Journal or Publication Title: Geological Society, London, Special Publications
Volume: 410
Page Range: SP410.11
Identification Number: 10.1144/SP410.11
Depositing User: Sarah Humbert
Date Deposited: 21 May 2015 16:42
Last Modified: 29 May 2015 15:42
URI: http://eprints.esc.cam.ac.uk/id/eprint/3295

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