Modeling Multi-Scale Deformation Cycles in Subduction Zones with a
Continuum Visco-Elastic-Brittle Framework
Abstract
The overwhelming amount of seismic, geodesic and in-situ observations
accumulated over the last 30 years clearly indicate that, from a
mechanical point of view, faults should be considered as both damageable
elastic solids in which highly localized features emerge as a result of
very short-term brittle processes and materials experiencing ductile
strains distributed in large volumes and over long time scales. The
interplay of both deformation mechanisms, brittle and ductile, give rise
to transient phenomena associating slow slip and tremors, known as slow
earthquakes, which dissipate a significant amount of stress in the fault
system. The physically-based numerical models developed to improve our
comprehension of the mechanical and dynamical behaviour of faults must
therefore have the capacity to treat simultaneously both deformation
mechanisms and to cover a wide range of time scales in a numerically
efficient manner. This capability is essential, both for simulating
accurately their deformation cycles and for improving our interpretation
of the available observations.
In this paper, we
present a numerically efficient visco-elasto-brittle numerical framework
that can simulate transient deformations akin to that observed in the
context of subduction zones, over the wide range of time scales relevant
for slow earthquakes. We implement the model in idealized simple shear
simulations and explore the sensitivity of its behavior to the value of
its main mechanical parameters.