Self-organized criticality model for earthquakes: Quiescence, foreshocks and aftershocks

We introduce a crust relaxation process in a continuous cellular automaton version of the Burridge-Knopoff model. Analogously to the original model, o ur model displays a robust power law distribution of event sizes (Gutenberg -Richter law). The principal new result obtained with our model is the spat iotemporal clustering of events exhibiting several characteristics of earth quakes in nature. Large events are accompanied by a precursory quiescence a nd by localized fore- and aftershocks. The increase of foreshock activity a s well as the decrease of aftershock activity follows a power law (Omori la w) with similar exponents p and q. All empirically observed power law expon ents, the Richter B-value, p and q and their variability can be reproduced simultaneously by our model, which depends mainly on the level of conservat ion and the relaxation time.