Properties of the aftershocks sequences of the 2000 and 2002 earthquakes in Aksehir-Afyon graben, west-central Anatolia, Turkey

Abstract

The b-value of the Gutenberg-Richter's frequency-magnitude relation and the p-value of the modified Omori law, which describes the decay rate of aftershock activity, were investigated for more than 500 aftershocks in the Aksehir-Afyon graben (AAG) following the 15 December 2000 Sultandagi-Aksehir and the 3 February 2002 Cay-Eber and Cobanlar earthquakes. We used the Kandilli Observatory's catalog, which contains records of aftershocks with magnitudes >= 2.5. For the Cobanlar earthquake, the estimated b-values for three aftershock sequences are in the range 0.34 <= b <= 2.85, with the exception of the one that occurred during the first hour (4.77), while the obtained p-values are in the range 0.44 <= p <= 1.77. The aftershocks of the Sultandagi earthquake have a high p-value, indicating fast decay of the aftershock activity. A regular increase of b can be observed, with b < 1.0 after 0.208 days for the Cay-Eber earthquake. A systematic and similar increase and decrease pattern exists for the b- and p-values of the Cobanlar earthquakes during the first 5 days.