Projects per year
Abstract
Using ground deformation data from Soufrière Hills volcano (SHV), we
present results from numerical modeling of the temperature- and
time-dependent stress evolution in a mechanically heterogeneous crust
prior to reservoir failure and renewed eruptive activity. The best fit
models do not allow us to discriminate between a magmatic plumbing
system consisting of either a single vertically elongated reservoir or a
series of stacked reservoirs. A prolate reservoir geometry with volumes
between 50 and 100 km3, reservoir pressure changes between 4 and 7 MPa, and reservoir volume changes between 0.03 and 0.04 km3 with magma compressibility between 4 × 10−11 and 1 × 10−9 Pa−1
provide plausible thermomechanical model parameters to explain the
deformation time series; around an order of magnitude less overpressure
than is generally inferred from homogeneous, elastic crustal models.
Reservoir failure is predicted to occur at the crest of the reservoir
except for reservoirs with highly compressible magma (
Pa) for which subhorizontal sill formation is predicted upon reservoir
failure. Introducing a deep-crustal hot zone modulates the partitioning
of strains into the hotter underlying crust and results in a further
reduction in overpressure estimates to values of around 1–2 MPa upon
reservoir failure. Deduced volume fluxes are consistent with constraints
from thermal modeling of active subvolcanic systems and imply dynamic
failure of a compressible magma mush column feeding eruptions at SHV.
Our interpretation of the results is that the combined thermomechanical
effects of a deep-crustal hot zone and hot encasing rocks around a
midcrustal andesitic reservoir fundamentally alter the time-dependent
subsurface stress and strain partitioning upon reservoir priming. These
effects substantially influence surface strains recorded by volcano
geodetic monitoring.
Original language | English |
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Pages (from-to) | 4626-4639 |
Number of pages | 14 |
Journal | Journal of Geophysical Research: Solid Earth |
Volume | 119 |
Issue number | 6 |
Early online date | 6 Jun 2014 |
DOIs | |
Publication status | Published - Jun 2014 |
Keywords
- magma
- ground deformation
- modeling
- FEM
- hot zone
Fingerprint
Dive into the research topics of 'The effects of thermomechanical heterogeneities in island arc crust on time-dependent preeruptive stresses and the failure of an andesitic reservoir'. Together they form a unique fingerprint.Projects
- 2 Finished
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Investigating the relationship between pluton growth and volcanism at an active intrusions in the central Andes
Gottsmann, J. (Principal Investigator)
1/10/09 → 1/01/14
Project: Research
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CYCLIC CHANGES IN THE GRAVITY FIELD AT SOUFRIERE HILLS VOLCANO, MONSERRAT
Gottsmann, J. (Principal Investigator)
1/05/07 → 1/11/09
Project: Research