Analysis of the temporal properties of Greek aftershock sequences

The temporal distribution of aftershock sequences can be analyzed by means of new parameters other than the Omori's p-value. A deep analysis of the temporal properties of six aftershock sequences occurred in Greece from 1980 to 1997 has been carried out by means of fractal tools. We performed the Omori's law, the R/S and the Allan Factor analyses in order to estimate the p-value of the aftershock rate. the Hurst exponent (H) of the interevent-time series, and the spectral exponent (alpha) respectively. Our results show a significant variability of the p-value from 0.89 to 1.48, of H from 0.78 to 1.186 and of alpha from 0.49 to 1.44. The variation of the normalized alpha with the threshold magnitude for all the aftershock sequences examined has displayed almost the same decreasing behaviour. The temporal fractality of aftershock sequences is primarily due to the power-law decay of the aftershock rate.