We investigate the validity of a proposed generalized Omori–Utsu law for the aftershock sequences for the Landers, Hector Mine, Northridge and Superstition Hills earthquakes, the four largest events in the southern California catalogue we analyse. This law unifies three of the most prominent empirical laws of statistical seismology—the Gutenberg–Richter law, the Omori–Utsu law, and a ge…