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Volcano load control on dyke propagation and vent distribution: Insights from analogue modeling

Kervyn M., Ernst G. G. J., van Wyk de Vries B., Mathieu Lucie et Jacobs P.. (2009). Volcano load control on dyke propagation and vent distribution: Insights from analogue modeling. Journal of geophysical research. Solid Earth, 114, (B03401), p. 1-26.

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URL officielle: https://doi.org/10.1029/2008JB005653

Résumé

The spatial distribution of eruptive vents around volcanoes can be complex and evolve as a volcano grows. Observations of vent distribution at contrasting volcanoes, from scoria cones to large shields, show that peripheral eruptive vents concentrate close to the volcano base. We use analogue experiments to explore the control of volcano load on magma ascent and on vent location. Results show that the local loading stress field favors eruption of rising magma away from the volcano summit if a central conduit is not established or is blocked. Two sets of scaled experiments are developed with contrasting rheological properties to analyze similarities and differences in simulated magma rise below a volcano: (1) Golden syrup (magma analogue) is injected into a sand-plaster mixed layer (crust analogue) under a cone; (2) water or air (magma analogues) is injected into gelatin under a sand cone. Rising dykes approaching the cone stress field are stopped by the load compressive stress. With continued intrusion, dyke overpressure builds up; dykes extend laterally until their tips are able to rise vertically again and to erupt in the flank or at the base of the volcano. Lateral offset of the extrusion point relative to the edifice summit depends on substratum thickness, volcano slope, and dyke overpressure. The 3D geometry of Golden syrup intrusions varies with experimental parameters from cylindrical conduits to dyke and sill complexes. Experimental results are compared with illustrative field cases and with previously published numerical models. This comparison enables applications and limitations of the analogue models to be highlighted and allows us to propose a conceptual model for the evolution of vent distribution with volcano growth.

Type de document:Article publié dans une revue avec comité d'évaluation
ISSN:0148-0227
Volume:114
Numéro:B03401
Pages:p. 1-26
Version évaluée par les pairs:Oui
Date:2009
Sujets:Sciences naturelles et génie > Sciences naturelles > Sciences de la terre (géologie, géographie)
Département, module, service et unité de recherche:Départements et modules > Département des sciences appliquées > Unité d'enseignement en sciences de la Terre
Mots-clés:volcano load, charge volcanique, analogue modeling, modélisation analogique, vent distribution, distribution de l'évacuation, evacuation vent
Déposé le:17 oct. 2019 22:23
Dernière modification:17 oct. 2019 22:23
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