Mechanical modeling of circumferential and radial dike intrusion on Galapagos volcanoes

Journal of Volcanology and Geothermal Research
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Abstract

A distinctive and unusual pattern of eruptive fissures is observed on the active volcanoes of the Galapagos islands, reflecting circumferential dike intrusion near the calderas and radial dike intrusion on the volcano flanks. Elastic finite-element models were used to investigate how a stress field could be produced and maintained to promote both circumferential and radial dike emplacement. Modeling results show that magma reservoirs of Galapagos volcanoes are probably diapiric, because this shape promotes both circumferential and radial intrusions, but magma pressure alone cannot create the observed pattern of dikes. Loading by volcano growth and magma reservoir pressure could produce a stress field of suitable orientation but insufficient magnitude. The intrusion of circumferential dikes could alter the stress field in a way that promotes future radial diking, and vice versa. Faulting or slumping within the calderas or on the volcano flanks in response to repeated intrusions could also create a stress field conducive to continued intrusion.

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Publication type Article
Publication Subtype Journal Article
Title Mechanical modeling of circumferential and radial dike intrusion on Galapagos volcanoes
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/0377-0273(94)00060-T
Volume 66
Issue 1-4
Year Published 1995
Language English
Publisher Elsevier
Description 16 p.
First page 37
Last page 52
Country Ecuador
Other Geospatial Galápagos Islands, Fernandina, Isabela
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