A simplified two-dimensional stick-slip model is introduced. The system shows a kind of dynamical order-disorder phase transition with a control parameter proportional to the strength of interaction. At the critical point, this model is consistent with the empirical laws of earthquakes such as Gutenberg-Richter's law, the spatial distribution of hypocenters, and the correlation function of the occurrence of earthquakes as results of a dynamical critical phenomenon. This model can naturally explain the locality that local magnitude distributions often deviate from Gutenberg-Richter's law. ¿American Geophysical Union 1991