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Article
The impact of rheology on the transition from stick‐slip to creep in a semi‐brittle analog
Journal of Geophysical Research: Solid Earth
  • Thomas Birren, Iowa State University
  • Jacqueline E. Reber, Iowa State University
Document Type
Article
Publication Version
Accepted Manuscript
Publication Date
2-24-2019
DOI
10.1029/2018JB016914
Abstract

Faults can release energy via a variety of different slip mechanisms ranging from steady creep to fast and destructive earthquakes. Tying the rheology of the crust to various slip dynamics is important for our understanding of plate tectonics and earthquake generation. Here, we propose that the interplay of fractures and viscous flow leads to a spectrum between stick-slip and creep. We use an elasto-visco-plastic rock analog (Carbopol U-21) where we vary the yield stress to investigate its impact on slip dynamics in shear experiments. The experiments are performed using a simple shear apparatus, which provides distributed shear across the entire width of the experiment and allows in situ observations of deformation. We record force and displacement during deformation and use time lapse photography to document fracture development. A low yield stress (25 Pa) leads to creep dynamics in the absence of fractures. An intermediate yield stress (144 Pa) leads to the development and interaction of opening (mode I) and shear (mode II) fractures. This interaction leads to a spectrum in slip dynamics ranging from creep to stick-slip. A high yield stress (357 Pa) results in the development of many mode I fractures and a deformation signal dominated by stick-slip. These results show that bulk yield stress, fracture formation, and slip dynamics are closely linked and can lead to a continuum between creep and stick-slip. We suggest that rheology should be considered as an additional mechanism to explain the broad range of slip dynamics in natural faults.

Comments

This is a manuscript of an article published as Birren, T., and J. E. Reber. "The impact of rheology on the transition from stick‐slip to creep in a semi‐brittle analog." Journal of Geophysical Research: Solid Earth. (2019). doi: 10.1029/2018JB016914. Posted with permission.

Research Data: https://doi.org/10.25380/iastate.7746635

Copyright Owner
American Geophysical Union
Language
en
File Format
application/pdf
Citation Information
Thomas Birren and Jacqueline E. Reber. "The impact of rheology on the transition from stick‐slip to creep in a semi‐brittle analog" Journal of Geophysical Research: Solid Earth (2019)
Available at: http://works.bepress.com/jacqueline-reber/7/