We discuss recent results on a new analysis regarding models showing Self-Organized Criticality (SOC), and in particular on the OFC one. We show that Probability Density Functions (PDFs) for the avalanche size differences at different times have fat tails with a q-Gaussian shape. This behavior does not depend on the time interval adopted and it is also found when considering energy differences between real earthquakes.

4 pages, Paper presented at the international conference CTNEXT07, satellite of STATPHYS23, 1-5 july 2007, Catania, Italy http://www.ct.infn.it/ctnext07/