Shear strain localization in elastodynamic rupture simulations

TL;DR

This paper investigates how shear strain localization affects earthquake fault dynamics by implementing Shear Transformation Zone (STZ) Theory into rupture models, revealing that localized slip leads to more intense and rapid ruptures.

Contribution

It introduces the application of STZ Theory to dynamic rupture models, demonstrating the impact of shear localization on fault slip behavior and stress release.

Findings

Localized slip enhances velocity weakening.

Localized ruptures have larger stress drops.

Higher peak slip rates in localized ruptures.

Abstract

We study strain localization as an enhanced velocity weakening mechanism on earthquake faults. Fault friction is modeled using Shear Transformation Zone (STZ) Theory, a microscopic physical model for non-affine rearrangements in granular fault gouge. STZ Theory is implemented in spring slider and dynamic rupture models of faults. We compare dynamic shear localization to deformation that is uniform throughout the gouge layer, and find that localized slip enhances the velocity weakening of the gouge. Localized elastodynamic ruptures have larger stress drops and higher peak slip rates than ruptures with homogeneous strain.