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Constructing constitutive relationships for seismic and aseismic fault slip

January 1, 2009

For the purpose of modeling natural fault slip, a useful result from an experimental fault mechanics study would be a physically-based constitutive relation that well characterizes all the relevant observations. This report describes an approach for constructing such equations. Where possible the construction intends to identify or, at least, attribute physical processes and contact scale physics to the observations such that the resulting relations can be extrapolated in conditions and scale between the laboratory and the Earth. The approach is developed as an alternative but is based on Ruina (1983) and is illustrated initially by constructing a couple of relations from that study. In addition, two example constitutive relationships are constructed; these describe laboratory observations not well-modeled by Ruina's equations: the unexpected shear-induced weakening of silica-rich rocks at high slip speed (Goldsby and Tullis, 2002) and fault strength in the brittle ductile transition zone (Shimamoto, 1986). The examples, provided as illustration, may also be useful for quantitative modeling.

Publication Year 2009
Title Constructing constitutive relationships for seismic and aseismic fault slip
DOI 10.1007/s00024-009-0523-0
Authors N.M. Beeler
Publication Type Article
Publication Subtype Journal Article
Series Title Pure and Applied Geophysics
Index ID 70036794
Record Source USGS Publications Warehouse
USGS Organization Cascades Volcano Observatory