Seismic and Transient Slip Characteristics of Heterogeneous Frictional-Viscous Shear Zones
Abstract
Both shallow and deep sections of the subduction interface in several modern subduction zones exhibit aseismic slow slip events, commonly accompanied by low frequency earthquakes. Observations from exhumed rocks suggest that the subduction interface in these regions is a shear zone in which frictional lenses are embedded in a weaker, distributed viscous matrix. Here we use seismo-mechanical modeling to explore the transient slip characteristics of finite-width frictional-viscous shear zones.
Our model formulation follows Herrendörfer et al. (JGR, 2018), which includes an invariant form of rate- and state-dependent friction (RSF) and simulates earthquakes along spontaneously evolving faults embedded in a 2D continuum. The setup includes two elastic plates bounding a viscoelastoplastic shear zone (subduction interface) with inclusions (clasts) of varying sizes, aspect ratios, densities and viscosity contrasts with respect to the surrounding matrix. The entire shear zone exhibits the same velocity-weakening RSF parameters, but the low viscosity matrix in the shear zone has the capacity to switch between RSF and linear viscous creep as a function of its prescribed viscosity and local stress state.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMT040.0016B
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGY;
- 8107 Continental neotectonics;
- TECTONOPHYSICS;
- 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS;
- 8163 Rheology and friction of fault zones;
- TECTONOPHYSICS