Declustering of the catalogue before 2002. (a) The magnitude against time with scaled colours based on background probability from 1995 to 2002. Orange probability of being background (near 1.0) and black aftershock seismicity (close to 0.0). Dotted line denotes M_c = 3.2. (b) Cumulative number of observed events with M_c ≥ 3.2 (black line) and cumulative number of background events (grey line). Background rate of subperiod 1 (Sbr1) and for subperiod 2 (Sbr2) are depicted in dotted and dotted–dashed lines. The ETAS result is shown in the grey box.