Fig. 12

Decays of aftershock rate over time for five mainshocks: a 1992 \({M}_{w}\) 7.3 Landers earthquake, b 1993 \({M}_{w}\) 7.8 Hokkaido–Nansei–Oki earthquake, c 1994 \({M}_{w}\) 7.7 Sanriku–Oki earthquake, d 1999 \({M}_{w}\) 7.4 Izmit earthquake, and e 2010 \({M}_{w}\) 7.2 Darfield earthquake. The solid black line represents the aftershock decay predicted from the modified Omori law. The horizontal dashed red line represents the background seismicity rate for 2 years before the main shock. The vertical dashed blue lines are the estimated durations of the aftershock sequence, where the aftershock rate first goes to the average daily background rate (red dashed line). The parameters representing the modified Omori law parameters (p, c, and k) are indicated in each panel