Self-organized criticality in stick-slip models with periodic boundaries

A spring-block model governed by threshold dynamics and driven by temporally increasing spring constants is investigated. Due to its novel multiplicative driving, criticality occurs even with periodic boundary conditions via a mechanism distinct from that of previous models. This mechanism is dictated by a coarsening process. The results show a high degree of universality. The observed behavior should be relevant to a class of systems approaching equilibrium via a punctuated threshold dynamics.