Open AccessPulse‐like, crack‐like, and supershear earthquake ruptures with shear strain localization
Author(s) -
Daub Eric G.,
Manning M. Lisa,
Carlson Jean M.
Publication year - 2010
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jb006388
Subject(s) - dissipation , shear (geology) , fault gouge , shear stress , earthquake rupture , fault (geology) , geology , mechanics , shear zone , seismology , strain energy , materials science , geotechnical engineering , composite material , physics , petrology , thermodynamics , tectonics , finite element method
We incorporate shear strain localization into spontaneous elastodynamic rupture simulations using a shear transformation zone (STZ) friction law. In the STZ model, plastic strain in the granular fault gouge occurs in local regions called STZs. The number density of STZs is governed by an effective disorder temperature, and regions with elevated effective temperature have an increased strain rate. STZ theory resolves the dynamic evolution of the effective temperature across the width of the fault zone. Shear bands spontaneously form in the model due to feedbacks amplifying heterogeneities in the initial effective temperature. In dynamic earthquake simulations, strain localization is a mechanism for dynamic fault weakening. A shear band dynamically forms, reduces the sliding stress, and decreases the frictional energy dissipation on the fault. We investigate the effect of the dynamic weakening due to localization in generating pulse‐like, crack‐like, and supershear rupture. Our results illustrate that the additional weakening and reduction of on‐fault energy dissipation due to localization have a significant impact on the initial shear stress required for supershear or pulse‐like rupture to propagate on a fault.