Modelling the lava dome extruded at Soufrière Hills Volcano, Montserrat, August 2005–May 2006: Part I: Dome shape and internal structure

Hale, A. J., Calder, E. S., Wadge, G., Loughlin, S. C. and Ryan, G. A. (2009) Modelling the lava dome extruded at Soufrière Hills Volcano, Montserrat, August 2005–May 2006: Part I: Dome shape and internal structure. Journal of Volcanology and Geothermal Research, 187 1-2: 53-68. doi:10.1016/j.jvolgeores.2009.08.023


Author Hale, A. J.
Calder, E. S.
Wadge, G.
Loughlin, S. C.
Ryan, G. A.
Title Modelling the lava dome extruded at Soufrière Hills Volcano, Montserrat, August 2005–May 2006: Part I: Dome shape and internal structure
Journal name Journal of Volcanology and Geothermal Research   Check publisher's open access policy
ISSN 0377-0273
1872-6097
Publication date 2009-10
Year available 2009
Sub-type Article (original research)
DOI 10.1016/j.jvolgeores.2009.08.023
Volume 187
Issue 1-2
Start page 53
End page 68
Total pages 16
Place of publication Eugene, OR
Publisher Elsevier
Language eng
Subject 040314 Volcanology
970104 Expanding Knowledge in the Earth Sciences
C1
Abstract Lava domes comprise core, carapace, and clastic talus components. They can grow endogenously by inflation of a core and/or exogenously with the extrusion of shear bounded lobes and whaleback lobes at the surface. Internal structure is paramount in determining the extent to which lava dome growth evolves stably, or conversely the propensity for collapse. The more core lava that exists within a dome, in both relative and absolute terms, the more explosive energy is available, both for large pyroclastic flows following collapse and in particular for lateral blast events following very rapid removal of lateral support to the dome. Knowledge of the location of the core lava within the dome is also relevant for hazard assessment purposes. A spreading toe, or lobe of core lava, over a talus substrate may be both relatively unstable and likely to accelerate to more violent activity during the early phases of a retrogressive collapse. Soufrière Hills Volcano, Montserrat has been erupting since 1995 and has produced numerous lava domes that have undergone repeated collapse events. We consider one continuous dome growth period, from August 2005 to May 2006 that resulted in a dome collapse event on 20th May 2006. The collapse event lasted 3 h, removing the whole dome plus dome remnants from a previous growth period in an unusually violent and rapid collapse event. We use an axisymmetrical computational Finite Element Method model for the growth and evolution of a lava dome. Our model comprises evolving core, carapace and talus components based on axisymmetrical endogenous dome growth, which permits us to model the interface between talus and core. Despite explicitly only modelling axisymmetrical endogenous dome growth our core–talus model simulates many of the observed growth characteristics of the 2005–2006 SHV lava dome well. Further, it is possible for our simulations to replicate large-scale exogenous characteristics when a considerable volume of talus has accumulated around the lower flanks of the dome. Model results suggest that dome core can override talus within a growing dome, potentially generating a region of significant weakness and a potential locus for collapse initiation.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Earth Systems Science Computational Centre Publications
 
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Created: Mon, 26 Apr 2010, 16:35:46 EST by Tracy Paroz on behalf of Earth Systems Science Computational Centre