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

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: 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 , where W_i is a material constant. The resulting relationship between shear strain and grain size seems to be compatible with existing experimental data.