Combining Multiphase Groundwater Flow and Slope Stability Models to Assess Stratovolcano Flank Collapse in the Cascade Range

Hydrothermal alteration can create low‐permeability zones, potentially resulting in elevated pore‐fluid pressures, within a volcanic edifice. Strength reduction by rock alteration and high pore‐fluid pressures have been suggested as a mechanism for edifice flank instability. Here we combine numerica...

Full description

Saved in:
Bibliographic Details
Published in:Journal of geophysical research. Solid earth 2018-04, Vol.123 (4), p.2787-2805
Main Authors: Ball, J. L., Taron, J., Reid, M. E., Hurwitz, S., Finn, C., Bedrosian, P.
Format: Article
Language:English
Subjects:
Collapse
Computer simulation
Control stability
Dimensional stability
flank collapse
Flow stability
Geophysics
Groundwater
Groundwater flow
Groundwater table
Heat transport
Hydrostatic pressure
Hydrothermal alteration
hydrothermal system
Instability
Intrusion
Lava
Magma
magmatic intrusion
Mathematical models
Mechanical properties
Membrane permeability
Multiphase
numerical modeling
Numerical models
Permeability
Pore water
Pore water pressure
Rocks
Safety
Saturation
Shear strength
Slope stability
Slopes
Stability analysis
volcano stability
Water
Water pressure
Water table
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Hydrothermal alteration can create low‐permeability zones, potentially resulting in elevated pore‐fluid pressures, within a volcanic edifice. Strength reduction by rock alteration and high pore‐fluid pressures have been suggested as a mechanism for edifice flank instability. Here we combine numerical models of multiphase heat transport and groundwater flow with a slope‐stability code that incorporates three‐dimensional distributions of strength and pore‐water pressure to address the following questions: (1) What permeability distributions and contrasts produce elevated pore‐fluid pressures in a stratovolcano? (2) What are the effects of these elevated pressures on flank stability? (3) Finally, what are the effects of magma intrusion on potential flank failure in an edifice? Simulation results show that under a range of plausible parameters, water tables in a stratovolcano can be elevated or perched. These elevated water tables result in universally lower stability (lower factor of safety) compared with equivalent dry edifices, indicating a higher likelihood of flank collapse. Low‐permeability (
ISSN:2169-9313
2169-9356
DOI:10.1002/2017JB015156