Morphologic variation of an evolving dome controlled by the extrusion of finite yield strength magma

Taha Husain, Derek Elsworth, Barry Voight, Glen Mattioli, Pamela Jansma

Research output: Contribution to journalArticle

Abstract

Degassing-induced crystallization in volatile rich intermediate composition magmas results in material stiffening and strengthening that prior to solidification is reflected in non-Newtonian rheology. We explore the effects of a spectrum of such rheological regimes on eruptive style and morphologic evolution of lava domes, using a two-dimensional (2D) particle-dynamics model for a spreading viscoplastic (Bingham) fluid. We assume that the ductile magma core of a 2D synthetic lava dome develops finite yield strength, and that deformable frictional talus evolves from a carapace that caps the magma core. Our new model is calibrated against an existing analytical model for a spreading viscoplastic lava dome and is further compared against observational data of lava dome growth. Results indicate that a degassing-induced increase in strength of the injected magma causes a transition in the lava dome morphology from a dome with low surface relief evolving endogenously (with apparent bulk yield strength - 10 4 < τ 0 a < 10 6 Pa), to a Pelean lava dome with spines (τ 0 a > 10 5 – 10 6 Pa) extruded through the dome carapace. The virtual lava dome with τ 0 a = 0.6 MPa shows good agreement with the observed dome heights observed at the Soufriere Hills Volcano, Montserrat during a period of endogenous growth. The calculated apparent flow viscosity (1.36 × 10 11 Pa·s for τ 0 a = 0.6 MPa) is in the range of estimated viscosities (10 9 to 10 12 Pa·s) for andesitic-dacitic crystal-rich lavas. Our model results indicate a strong correlation between apparent yield strength and dome morphology, with both controlled by degassing-induced crystallization and extrusion rate.

Original languageEnglish (US)
Pages (from-to)51-64
Number of pages14
JournalJournal of Volcanology and Geothermal Research
Volume370
DOIs
StatePublished - Jan 15 2019

Fingerprint

lava dome
Domes
yield strength
domes
extrusion
magma
dome
Extrusion
Yield stress
lava
degassing
Degassing
crystallization
viscosity
endogenous growth
Crystallization
talus
solidification
rheology
Viscosity

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

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title = "Morphologic variation of an evolving dome controlled by the extrusion of finite yield strength magma",
abstract = "Degassing-induced crystallization in volatile rich intermediate composition magmas results in material stiffening and strengthening that prior to solidification is reflected in non-Newtonian rheology. We explore the effects of a spectrum of such rheological regimes on eruptive style and morphologic evolution of lava domes, using a two-dimensional (2D) particle-dynamics model for a spreading viscoplastic (Bingham) fluid. We assume that the ductile magma core of a 2D synthetic lava dome develops finite yield strength, and that deformable frictional talus evolves from a carapace that caps the magma core. Our new model is calibrated against an existing analytical model for a spreading viscoplastic lava dome and is further compared against observational data of lava dome growth. Results indicate that a degassing-induced increase in strength of the injected magma causes a transition in the lava dome morphology from a dome with low surface relief evolving endogenously (with apparent bulk yield strength - 10 4 < τ 0 a < 10 6 Pa), to a Pelean lava dome with spines (τ 0 a > 10 5 – 10 6 Pa) extruded through the dome carapace. The virtual lava dome with τ 0 a = 0.6 MPa shows good agreement with the observed dome heights observed at the Soufriere Hills Volcano, Montserrat during a period of endogenous growth. The calculated apparent flow viscosity (1.36 × 10 11 Pa·s for τ 0 a = 0.6 MPa) is in the range of estimated viscosities (10 9 to 10 12 Pa·s) for andesitic-dacitic crystal-rich lavas. Our model results indicate a strong correlation between apparent yield strength and dome morphology, with both controlled by degassing-induced crystallization and extrusion rate.",
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Morphologic variation of an evolving dome controlled by the extrusion of finite yield strength magma. / Husain, Taha; Elsworth, Derek; Voight, Barry; Mattioli, Glen; Jansma, Pamela.

In: Journal of Volcanology and Geothermal Research, Vol. 370, 15.01.2019, p. 51-64.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Morphologic variation of an evolving dome controlled by the extrusion of finite yield strength magma

AU - Husain, Taha

AU - Elsworth, Derek

AU - Voight, Barry

AU - Mattioli, Glen

AU - Jansma, Pamela

PY - 2019/1/15

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N2 - Degassing-induced crystallization in volatile rich intermediate composition magmas results in material stiffening and strengthening that prior to solidification is reflected in non-Newtonian rheology. We explore the effects of a spectrum of such rheological regimes on eruptive style and morphologic evolution of lava domes, using a two-dimensional (2D) particle-dynamics model for a spreading viscoplastic (Bingham) fluid. We assume that the ductile magma core of a 2D synthetic lava dome develops finite yield strength, and that deformable frictional talus evolves from a carapace that caps the magma core. Our new model is calibrated against an existing analytical model for a spreading viscoplastic lava dome and is further compared against observational data of lava dome growth. Results indicate that a degassing-induced increase in strength of the injected magma causes a transition in the lava dome morphology from a dome with low surface relief evolving endogenously (with apparent bulk yield strength - 10 4 < τ 0 a < 10 6 Pa), to a Pelean lava dome with spines (τ 0 a > 10 5 – 10 6 Pa) extruded through the dome carapace. The virtual lava dome with τ 0 a = 0.6 MPa shows good agreement with the observed dome heights observed at the Soufriere Hills Volcano, Montserrat during a period of endogenous growth. The calculated apparent flow viscosity (1.36 × 10 11 Pa·s for τ 0 a = 0.6 MPa) is in the range of estimated viscosities (10 9 to 10 12 Pa·s) for andesitic-dacitic crystal-rich lavas. Our model results indicate a strong correlation between apparent yield strength and dome morphology, with both controlled by degassing-induced crystallization and extrusion rate.

AB - Degassing-induced crystallization in volatile rich intermediate composition magmas results in material stiffening and strengthening that prior to solidification is reflected in non-Newtonian rheology. We explore the effects of a spectrum of such rheological regimes on eruptive style and morphologic evolution of lava domes, using a two-dimensional (2D) particle-dynamics model for a spreading viscoplastic (Bingham) fluid. We assume that the ductile magma core of a 2D synthetic lava dome develops finite yield strength, and that deformable frictional talus evolves from a carapace that caps the magma core. Our new model is calibrated against an existing analytical model for a spreading viscoplastic lava dome and is further compared against observational data of lava dome growth. Results indicate that a degassing-induced increase in strength of the injected magma causes a transition in the lava dome morphology from a dome with low surface relief evolving endogenously (with apparent bulk yield strength - 10 4 < τ 0 a < 10 6 Pa), to a Pelean lava dome with spines (τ 0 a > 10 5 – 10 6 Pa) extruded through the dome carapace. The virtual lava dome with τ 0 a = 0.6 MPa shows good agreement with the observed dome heights observed at the Soufriere Hills Volcano, Montserrat during a period of endogenous growth. The calculated apparent flow viscosity (1.36 × 10 11 Pa·s for τ 0 a = 0.6 MPa) is in the range of estimated viscosities (10 9 to 10 12 Pa·s) for andesitic-dacitic crystal-rich lavas. Our model results indicate a strong correlation between apparent yield strength and dome morphology, with both controlled by degassing-induced crystallization and extrusion rate.

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JF - Journal of Volcanology and Geothermal Research

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