Fig. 6From: Aftershocks following the 2011 Tohoku-Oki earthquake driven by both stress transfer and afterslipSpatial distributions of the numbers of background earthquakes and similar earthquakes during the 11/03/2011–11/03/2020 period. a Spatial distribution of the number of background earthquakes calculated using the estimated HIST-ETAS model. b Spatial distribution of the number of similar earthquakes (\(M_{{\text{j}}} \ge 4.0\)) (Igarashi 2020). Black dashed and blue solid lines are the same as in Fig. 3Back to article page