How Accurately Can We Model Magma Reservoir Failure With Uncertainties in Host Rock Rheology?

Research output: Contribution to journalArticle

Abstract

Forecasting the onset of a volcanic eruption from a closed system requires understanding its stress state and failure potential, which can be investigated through numerical modeling. However, the lack of constraints on model parameters, especially rheology, may substantially impair the accuracy of failure forecasts. Therefore, it is essential to know whether large variations and uncertainties in rock properties will preclude the ability of models to predict reservoir failure. A series of two-dimensional, axisymmetric models are used to investigate sensitivities of brittle failure initiation to assumed rock properties. The numerical experiments indicate that the deformation and overpressure at failure onset simulated by elastic models will be much lower than the viscoelastic models, when the timescale of pressurization exceeds the viscoelastic relaxation time of the host rock. Poisson's ratio and internal friction angle have much less effect on failure forecasts than Young's modulus. Variations in Young's modulus significantly affect the prediction of surface deformation before failure onset when Young's modulus is ' 40 GPa. Longer precursory volcano-tectonic events may occur in weak host rock (E ' 40 GPa) due to well-developed Coulomb failure prior to dike propagation. Thus, combining surface deformation with seismicity may enhance the accuracy of eruption forecast in these situations. Compared to large and oblate magma systems, small and prolate systems create far less surface uplift prior to failure initiation, suggesting that more frequent measurements are necessary.

Original languageEnglish (US)
Pages (from-to)8030-8042
Number of pages13
JournalJournal of Geophysical Research: Solid Earth
Volume124
Issue number8
DOIs
StatePublished - Aug 1 2019

Fingerprint

rheology
Rheology
magma chamber
host rock
magma
Rocks
rocks
Young modulus
Elastic moduli
rock property
forecasting
Volcanic Eruptions
volcanic eruption
Phosmet
modulus of elasticity
weak rock
brittle failure
Levees
Volcanoes
Pressurization

Keywords

  • failure
  • numerical modeling
  • precursory deformation
  • rock properties
  • volcanic eruption

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

How Accurately Can We Model Magma Reservoir Failure With Uncertainties in Host Rock Rheology? / Zhan, Y.; Gregg, Patricia.

In: Journal of Geophysical Research: Solid Earth, Vol. 124, No. 8, 01.08.2019, p. 8030-8042.

Research output: Contribution to journalArticle

@article{e03b15980fb140c9b319eafd6aba566f,
title = "How Accurately Can We Model Magma Reservoir Failure With Uncertainties in Host Rock Rheology?",
abstract = "Forecasting the onset of a volcanic eruption from a closed system requires understanding its stress state and failure potential, which can be investigated through numerical modeling. However, the lack of constraints on model parameters, especially rheology, may substantially impair the accuracy of failure forecasts. Therefore, it is essential to know whether large variations and uncertainties in rock properties will preclude the ability of models to predict reservoir failure. A series of two-dimensional, axisymmetric models are used to investigate sensitivities of brittle failure initiation to assumed rock properties. The numerical experiments indicate that the deformation and overpressure at failure onset simulated by elastic models will be much lower than the viscoelastic models, when the timescale of pressurization exceeds the viscoelastic relaxation time of the host rock. Poisson's ratio and internal friction angle have much less effect on failure forecasts than Young's modulus. Variations in Young's modulus significantly affect the prediction of surface deformation before failure onset when Young's modulus is ' 40 GPa. Longer precursory volcano-tectonic events may occur in weak host rock (E ' 40 GPa) due to well-developed Coulomb failure prior to dike propagation. Thus, combining surface deformation with seismicity may enhance the accuracy of eruption forecast in these situations. Compared to large and oblate magma systems, small and prolate systems create far less surface uplift prior to failure initiation, suggesting that more frequent measurements are necessary.",
keywords = "failure, numerical modeling, precursory deformation, rock properties, volcanic eruption",
author = "Y. Zhan and Patricia Gregg",
year = "2019",
month = "8",
day = "1",
doi = "10.1029/2019JB018178",
language = "English (US)",
volume = "124",
pages = "8030--8042",
journal = "Journal of Geophysical Research D: Atmospheres",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "8",

}

TY - JOUR

T1 - How Accurately Can We Model Magma Reservoir Failure With Uncertainties in Host Rock Rheology?

AU - Zhan, Y.

AU - Gregg, Patricia

PY - 2019/8/1

Y1 - 2019/8/1

N2 - Forecasting the onset of a volcanic eruption from a closed system requires understanding its stress state and failure potential, which can be investigated through numerical modeling. However, the lack of constraints on model parameters, especially rheology, may substantially impair the accuracy of failure forecasts. Therefore, it is essential to know whether large variations and uncertainties in rock properties will preclude the ability of models to predict reservoir failure. A series of two-dimensional, axisymmetric models are used to investigate sensitivities of brittle failure initiation to assumed rock properties. The numerical experiments indicate that the deformation and overpressure at failure onset simulated by elastic models will be much lower than the viscoelastic models, when the timescale of pressurization exceeds the viscoelastic relaxation time of the host rock. Poisson's ratio and internal friction angle have much less effect on failure forecasts than Young's modulus. Variations in Young's modulus significantly affect the prediction of surface deformation before failure onset when Young's modulus is ' 40 GPa. Longer precursory volcano-tectonic events may occur in weak host rock (E ' 40 GPa) due to well-developed Coulomb failure prior to dike propagation. Thus, combining surface deformation with seismicity may enhance the accuracy of eruption forecast in these situations. Compared to large and oblate magma systems, small and prolate systems create far less surface uplift prior to failure initiation, suggesting that more frequent measurements are necessary.

AB - Forecasting the onset of a volcanic eruption from a closed system requires understanding its stress state and failure potential, which can be investigated through numerical modeling. However, the lack of constraints on model parameters, especially rheology, may substantially impair the accuracy of failure forecasts. Therefore, it is essential to know whether large variations and uncertainties in rock properties will preclude the ability of models to predict reservoir failure. A series of two-dimensional, axisymmetric models are used to investigate sensitivities of brittle failure initiation to assumed rock properties. The numerical experiments indicate that the deformation and overpressure at failure onset simulated by elastic models will be much lower than the viscoelastic models, when the timescale of pressurization exceeds the viscoelastic relaxation time of the host rock. Poisson's ratio and internal friction angle have much less effect on failure forecasts than Young's modulus. Variations in Young's modulus significantly affect the prediction of surface deformation before failure onset when Young's modulus is ' 40 GPa. Longer precursory volcano-tectonic events may occur in weak host rock (E ' 40 GPa) due to well-developed Coulomb failure prior to dike propagation. Thus, combining surface deformation with seismicity may enhance the accuracy of eruption forecast in these situations. Compared to large and oblate magma systems, small and prolate systems create far less surface uplift prior to failure initiation, suggesting that more frequent measurements are necessary.

KW - failure

KW - numerical modeling

KW - precursory deformation

KW - rock properties

KW - volcanic eruption

UR - http://www.scopus.com/inward/record.url?scp=85070769011&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85070769011&partnerID=8YFLogxK

U2 - 10.1029/2019JB018178

DO - 10.1029/2019JB018178

M3 - Article

AN - SCOPUS:85070769011

VL - 124

SP - 8030

EP - 8042

JO - Journal of Geophysical Research D: Atmospheres

JF - Journal of Geophysical Research D: Atmospheres

SN - 0148-0227

IS - 8

ER -