Critical Sensitivity in Driven Nonlinear Threshold Systems

— Rupture in heterogeneous brittle media, including earthquakes, can be regarded as complicated phenomena in driven nonlinear threshold systems. It displays catastrophe transition and sample-specificity, which results in difficulty of rupture prediction. Our numerical simulations indicate that critical sensitivity might be a common precursor of catastrophe transition and thus give a clue to catastrophe prediction. In this paper we present an analytical examination of critical sensitivity in driven nonlinear threshold systems, based on mean field approximation and damage relaxation time model. The result suggests that critical sensitivity is in reality a common feature prior to catastrophe transition in driven nonlinear threshold systems, with disordered mesoscopic heterogeneity. This result seems to be supported by rock experiments.