Fig. 6

ETAS estimate for aftershock activity (M ≥ 3.0) to the target period from the main shock (iii) until 8.6 days had elapsed (14th Sept. 2018) (with the estimation period and estimated parameters printed in black), and then extrapolated to the rest of the period. The ordinary time plot is on the left, transformed time plot is on the right. The empirical cumulative (black) curve deviated downwards outside the twofold error parabola from the expected trend, showing relative quiescence after the change-point. The dashed cumulative curves show those of the reference ETAS model for the entire period (with the estimation period and estimated parameters in gray). See Additional file 1: Table S6 for the fitting configurations and results of model comparisons