We suggest a model that describes a mutual dynamic of tectonic plates. The
dynamic is a sort of stick-slip one which is modeled by a Markov random
process. The process defines a microlevel of the dynamic. A macrolevel is
obtained by a scaling limit which leads to a system of integro-differential
equations which determines a kind of mean field systems. Conditions when
Gutenberg-Richter empirical law are presented on the mean field level. These
conditions are rather universal and do not depend on features of resistant
forces.Comment: 3 figure