The Pressure and Temperature Dependence of the Shear Strength of Minerals

Shear-strength measurements on diopside, labradorite, and olivine were made in the pressure range to 50 kbar and in the temperature range to 900°C. The data were correlated with a semiempirical formula which describes the pressure and temperature dependence of the shear strength within experimental error. The formulation provides a useful synthesis of the data whereby three constants characterize each material. In addition, the formulation provides a basis for extrapolation so that the shear strength of a material can be estimated at pressures or temperatures beyond the range of experiment.