The Role of Shear Fabric in Controlling Breakdown Processes During Laboratory Slow-Slip Events

23Citations
Citations of this article
37Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Understanding the physical mechanisms at the origin of slow-slip events has been proven a very challenging task. In particular, little is known on the role of fault heterogeneity during slow slip. In this study, we provide evidences that fault fabric controls slip velocity time histories during slow-slip events generated in the laboratory. We performed experiments using a double-direct biaxial shear apparatus and two different fault gouges, homogeneous quartz powder, and heterogeneous anhydrite/dolomite mixture. We measure details of fault slip to resolve the slip velocity function and volumetric deformation that, coupled with an analysis of the resulting microstructure, allow us to infer the mechanical processes at play. Our results show that slow-slip events can be generated for both fault gouges when k ~ kc with similar values of breakdown work. The shear fabric exerts a strong influence during the coseismic breakdown stage. In quartz, where most of the slip occurs on a very localized slipping surface, the peak slip velocity is attained near the final stage of friction breakdown and therefore a relevant amount of the mechanical work is absorbed during slip acceleration. In anhydrite/dolomite mixture, the peak slip velocity is suddenly reached after a relatively small drop in friction, accompanied by fault dilation, implying that most of the mechanical work is absorbed during slip deceleration. For anhydrite/dolomite mixture these results are likely related to heterogeneous slip distribution along the observed foliation. Taken together, these observations suggest that the mechanics of slow-slip events depends on shear zone fabric.

Cite

CITATION STYLE

APA

Scuderi, M. M., Tinti, E., Cocco, M., & Collettini, C. (2020). The Role of Shear Fabric in Controlling Breakdown Processes During Laboratory Slow-Slip Events. Journal of Geophysical Research: Solid Earth, 125(11). https://doi.org/10.1029/2020JB020405

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free