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Fig. 2 | Earth, Planets and Space

Fig. 2

From: Characteristics of seismic activity before and after the 2018 M6.7 Hokkaido Eastern Iburi earthquake

Fig. 2

Two-stage ETAS model fittings during stable period (from 2-Apr-1998 to 20-Oct-2016) before the M6.7 main shock (iii, 6-Sep-2018). Black curves show the observed cumulative number of M ≥ 1.5 earthquakes from the 2-Apr.-1998. Red curves show the estimated theoretical curve for the target interval from the day of occurrence of the M8.0 Tokachi-Oki earthquake (i, 26-Sep-2003) until the date of the activated seismicity (20-Oct-2016, t = 6733.35 days from 2-Apr-1998) that led to the M5.1 event (ii, 1-Jul-2017). The estimation period and estimated parameters are printed in black. The left and right plots are in the ordinary time and transformed time (ETAS RPP time), respectively. The parabola shows 2-sigma error bound. The dashed red cumulative curve in each panel shows that of the reference ETAS model fitted for the period from 6-Sep-2018 to 20-Oct-2016. The estimation period and estimated parameters are printed in gray. The blue circles show the depths of the hypocenter against transformed time. Magnitudes against ordinary time (vertical bars) and transformed time (+ signs), regarding the fitted ETAS model, are also plotted. See Additional file 1: Table S2 for the fitting configurations, parameter estimates, and the results of model comparisons

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