Fig. 2

Evolution of activity in the seismic clusters outlined in Fig. 1. a Cumulative number of earthquakes in each cluster. Time is measured from August 2003 and each curve is normalized to its final value. The dashed lines show the occurrence times of the large earthquakes discussed in the text. The gray dashed line shows the average of all clusters. The legend indicates the names of the clusters (see Fig. 1 for their locations). b Seismicity rates in each cluster. The upper black trace is the mean of the rates for all clusters. The names of the clusters are displayed on the left. The time series are displayed at increasing longitudes. The color scale shown on the lower right corner refers to the normalized cumulative number of earthquakes