Similarities between Shear Zones of Different Magnitudes

An examination is made of the formation and development of shear zone structures on (1) the microscopic scale in the shear box test, (2) an intermediate scale in the Riedel experiment, and (3) the regional scale in the earthquake fault. On the basis of the resistance to shear, three structural stages are chosen for detailed study: the peak structure occurring at peak shearing resistance, the post-peak structure occurring after peak shearing resistance, and the residual structure occurring at residual shearing resistance. Most of the similarities in structure between the different scales at each of these stages are interpreted in terms of the mechanical properties of the material, the Coulomb failure criterion, and the kinematic restraints inherent in the type of deformation. Other similarities which are not as yet understood are described and suggested as topics for future research.