A comparative analysis of continuum plasticity, viscoplasticity and phase-field models for earthquake sequence modeling
Open access
Date
2023-10Type
- Journal Article
Abstract
This paper discusses continuum models for simulating earthquake sequences on faults governed by rate-and-state dependent friction. Through detailed numerical analysis of a conventional strike-slip fault, new observations regarding the use of various continuum earthquake models are presented. We update a recently proposed plasticity-based model using a consistently linearized formulation, show its agreement with discrete fault models for fault thicknesses of hundreds of meters, and demonstrate mesh objectivity for slip-related variables. To obtain a fully regularized fault width description with an internal length scale, we study the performance and mesh convergence of a plasticity-based model complemented by a Kelvin viscosity term and the phase-field approach to cohesive fracture. The Kelvin viscoplasticity-based model can introduce an internal length scale and a mesh-objective response. However, on grid sizes down to meters, this only holds for very high Kelvin viscosities that inhibit seismic slip rates, which renders this approach impractical for simulating earthquake sequences. On the other hand, our phase-field implementation for earthquake sequences provides a numerically robust framework that agrees with a discrete reference solution, is mesh objective, and reaches seismic slip rates. The model, unsurprisingly, requires highly refined grids around the fault zones to reproduce results close to a discrete model. Following this line, the effect of an internal length scale parameter on the phase-field predictions and mesh convergence are discussed. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000607036Publication status
publishedExternal links
Journal / series
Computational MechanicsVolume
Pages / Article No.
Publisher
SpringerSubject
Earthquake dynamics; Strain localisation; Kelvin viscoplasticity; Phase-field methodOrganisational unit
03698 - Tackley, Paul / Tackley, Paul
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