Fig. 9.

(a) Expected number of M ≥ 5 earthquakes in 2009, calculated from the combination of background rate of M ≥ 3 shocks and spatially variable b-values. Note that no coseismic stress changes are considered for calculations to obtain the results in this figure. In other words, all ΔCFF values for all the large earthquakes are assumed to be zero. (b) Expected number of M ≥ 5 earthquakes in 2009 reproduced by our method but with the spatially constant b-value (b = 0.92). Note that the influence of the stress perturbations due to the historical earthquakes results in different forecasted rates compared to the case of no-stress-effect (Fig. 9(a)). (c) Expected number of M ≥ 5 earthquakes in 2009 reproduced by our method with spatially variable b-value. (d) Earthquakes observed in 2009, in mainland Japan. On-fault and off-fault aftershocks of the recent inland large earthquakes can be reproduced by our approach. However, temporal swarm activities and high rate of continuous seismicity near Sagami and Suruga troughs in Izu and Kanto regions are hardly forecasted.