Dynamical scaling and generalized Omori law

The power law decay of the aftershocks rate is observed only after a characteristic time scale c. The dependence of c on the mainshock magnitude MM and on the lower cut-off magnitude M-I is well established. By considering ten sequences recorded in the California Catalog we show that the aftershock number distribution becomes independent of both M-M and M-I if time is rescaled by an appropriate time scale fixed by the difference M-M - M-I. This result is interpreted within a more general dynamical scaling hypothesis recently formulated, relating time differences to magnitude differences. The above hypothesis gives predictions in good agreement with the recent findings by Peng et al. ( 2007). Citation: Lippiello, E., M. Bottiglieri, C. Godano, and L. de Arcangelis ( 2007), Dynamical scaling and generalized Omori law.