Simulating stick‐slip failure in a sheared granular layer using a physics‐based constitutive model. Issue 1 (28th January 2017)

• Record Type: Journal Article
• Authors: Lieou, Charles K. C.; Daub, Eric G.; Guyer, Robert A.; Ecke, Robert E.; Marone, Chris; Johnson, Paul A.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 1(2017)
• Page Start: 295
• Page End: 307
• Publication Date: 2017-01-28
• Subjects: rate‐and‐state -- friction -- stick slip -- gouge -- constitutive law -- failure; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1002/2016JB013627
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: We model laboratory earthquakes in a biaxial shear apparatus using the Shear‐Transformation‐Zone (STZ) theory of dense granular flow. The theory is based on the observation that slip events in a granular layer are attributed to grain rearrangement at soft spots called STZs, which can be characterized according to principles of statistical physics. We model lab data on granular shear using STZ theory and document direct connections between the STZ approach and rate‐and‐state friction. We discuss the stability transition from stable shear to stick‐slip failure and show that stick slip is predicted by STZ when the applied shear load exceeds a threshold value that is modulated by elastic stiffness and frictional rheology. We also show that STZ theory mimics fault zone dilation during the stick phase, consistent with lab observations. Key Points: Physics‐based constitutive model for lab earthquakes reproduces key observations We establish direct connection between the STZ model and rate‐and‐state friction Stick‐slip instabilities predicted by STZ model