Grain size as an indication of shear strain in brittle fault zones

Abstract

Shear strain γ in brittle fault zones is related to final and initial grain size parameters, d f and d i , respectively, by an expression of the form: γ = ƒ(d f,d i) μ kσ n where μ k the coefficient of kinetic friction of crushed rock and σ n the normal stress across the zone at the time of faulting. Technological literature suggests that ƒ(d f, d i) may be given by 10 W i(d f − 1 2 −d i − 1 2 ) , where W i is a material constant. The resulting relationship between shear strain and grain size seems to be compatible with existing experimental data.