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Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile

Moving beyond the widely used kinematic models for the deformation sources, we present a new dynamic model to describe the process of injecting magma into an existing magma reservoir. To validate this model, we derive an analytical solution and compare its results to those calculated using the Finit...

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Autores principales: Le Mével, Hélène, Gregg, Patricia M., Feigl, Kurt L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101856/
https://www.ncbi.nlm.nih.gov/pubmed/27867790
http://dx.doi.org/10.1002/2016JB013066
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author Le Mével, Hélène
Gregg, Patricia M.
Feigl, Kurt L.
author_facet Le Mével, Hélène
Gregg, Patricia M.
Feigl, Kurt L.
author_sort Le Mével, Hélène
collection PubMed
description Moving beyond the widely used kinematic models for the deformation sources, we present a new dynamic model to describe the process of injecting magma into an existing magma reservoir. To validate this model, we derive an analytical solution and compare its results to those calculated using the Finite Element Method. A Newtonian fluid characterized by its viscosity, density, and overpressure (relative to the lithostatic value) flows through a vertical conduit, intruding into a reservoir embedded in an elastic domain, leading to an increase in reservoir pressure and time‐dependent surface deformation. We apply our injection model to Interferometric Synthetic Aperture Radar (InSAR) data from the ongoing unrest episode at Laguna del Maule (Chile) volcanic field that started in 2007. Using a grid search optimization, we minimize the misfit to the InSAR displacement data and vary the three parameters governing the analytical solution: the characteristic timescale τ (P) for magma propagation, the maximum injection pressure, and the inflection time when the acceleration switches from positive to negative. For a spheroid with semimajor axis a = 6200 m, semiminor axis c = 100 m, located at a depth of 4.5 km in a purely elastic half‐space, the best fit to the InSAR displacement data occurs for τ (P)=9.5 years and an injection pressure rising up to 11.5 MPa for 2 years. The volume flow rate increased to 1.2 m(3)/s for 2 years and then decreased to 0.7 m(3)/s in 2014. In 7.3 years, at least 187 × 10(6) m(3) of magma was injected.
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spelling pubmed-51018562016-11-16 Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile Le Mével, Hélène Gregg, Patricia M. Feigl, Kurt L. J Geophys Res Solid Earth Research Articles Moving beyond the widely used kinematic models for the deformation sources, we present a new dynamic model to describe the process of injecting magma into an existing magma reservoir. To validate this model, we derive an analytical solution and compare its results to those calculated using the Finite Element Method. A Newtonian fluid characterized by its viscosity, density, and overpressure (relative to the lithostatic value) flows through a vertical conduit, intruding into a reservoir embedded in an elastic domain, leading to an increase in reservoir pressure and time‐dependent surface deformation. We apply our injection model to Interferometric Synthetic Aperture Radar (InSAR) data from the ongoing unrest episode at Laguna del Maule (Chile) volcanic field that started in 2007. Using a grid search optimization, we minimize the misfit to the InSAR displacement data and vary the three parameters governing the analytical solution: the characteristic timescale τ (P) for magma propagation, the maximum injection pressure, and the inflection time when the acceleration switches from positive to negative. For a spheroid with semimajor axis a = 6200 m, semiminor axis c = 100 m, located at a depth of 4.5 km in a purely elastic half‐space, the best fit to the InSAR displacement data occurs for τ (P)=9.5 years and an injection pressure rising up to 11.5 MPa for 2 years. The volume flow rate increased to 1.2 m(3)/s for 2 years and then decreased to 0.7 m(3)/s in 2014. In 7.3 years, at least 187 × 10(6) m(3) of magma was injected. John Wiley and Sons Inc. 2016-08-04 2016-08 /pmc/articles/PMC5101856/ /pubmed/27867790 http://dx.doi.org/10.1002/2016JB013066 Text en ©2016. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs (http://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle Research Articles
Le Mével, Hélène
Gregg, Patricia M.
Feigl, Kurt L.
Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title_full Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title_fullStr Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title_full_unstemmed Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title_short Magma injection into a long‐lived reservoir to explain geodetically measured uplift: Application to the 2007–2014 unrest episode at Laguna del Maule volcanic field, Chile
title_sort magma injection into a long‐lived reservoir to explain geodetically measured uplift: application to the 2007–2014 unrest episode at laguna del maule volcanic field, chile
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101856/
https://www.ncbi.nlm.nih.gov/pubmed/27867790
http://dx.doi.org/10.1002/2016JB013066
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