Activity criterion of pre-existing fabrics in non-homogeneous deformation domain

Abstract

The Anderson’s model can be applied only to elastic homogeneous deformation and cannot explain complicated phenomena of natural faults, which to a large degree limits the model to practical application. By combing the Coulomb-Mohr Criterion with the sandbox modeling and considering non-homogeneous deformation, mechanisms of how basement pre-existing fabrics control fault formation and evolution are analyzed and a mechanical factor, activation-coefficient (faS) of pre-existing fabrics, is proposed. It is determined by the attitude and mechanical properties of pre-existing fabric, and the stress state (the magnitudes and directions of the three principal stresses). The coefficient has taken the heterogeneity of rocks into account and may serve as a criterion for evaluating the activity of a pre-existing fabric. The Mohr-Coulomb Criterion is expanded to non-homogeneous deformation domain in terms of activation-coefficient (faS) of pre-existing fabrics, the general law of the activity of a pre-existing fabric is predicted, the fault complexity real of rift basin is revealed in theory, and the controlling law of basement pre-existing faults to fault formation and evolution is determined, and checked with sandbox modeling. A new way is provided for in-depth study of faulting.