A non-extensive approach in investigating the seismicity of L'Aquila area (central Italy), struck by the 6 April 2009 earthquake (M-L=5.8)

P>Using the non-extensive statistics, the analysis of the magnitude distribution of the 2005-2009 seismicity of L'Aquila area (Central Italy), struck by a strong earthquake (M-L = 5.8) on 6 April 2009 (1:32 UTC), was performed. This was the strongest event of the sequence. The analysis of the frequency magnitude distribution of three time intervals - (1) from 16 April 2005 to 30 March 2009, (2) from 30 March 2009 to 6 April 2009, and (3) from 6 April 2009 to 1 July 2009 - reveals that the non-extensivity parameter q increases in the seismic interval (2), before the occurrence of the strongest L'Aquila event, indicating an increase in the degree of out-of-equilibrium state before the occurrence of the strongest event.