New evidences of earthquake occurrence as a self-organized critically process

One of the tools of natural hazards mitigation is to find a way to predict the natural phenomenon, that is, the specification of the time, location and strength of a future natural phenomenon under study within stated limits. The first condition to carry out a prediction is to dispose of a physical model that accounts for the phenomenon under study. For the specific case of earthquake prediction, it is weil known that an earthquake results from a sudden slip on a geological fault due to a stress concentration that exceeds the resistance of the material. In its turn, the stress concentration is caused by the dynamics of the plate tectonics. The fracture and failure problems are notoriously intractable due to the heterogeneous state of the Earth. One way to override this difficulty is by means of the use of statistical mechanics applied to the study of simple models, such as the composite spring-block slider model of Burridge and Knopoff (1967) and the self-organized criticality model of Bak and Tang (1989). Both models lead to similar results, one of which is of fundamental importance to the study of earthquake hazard: earthquake cannot be predicted because any small rupture has some probability of cascading into a large event. Hence, it is of the major importance to test these models against real data.