Non-Poisson distribution of the time distances between two consecutive   clusters of earthquakes
  With the help of the Diffusion Entropy technique we show the non-Poisson statistics of the distances between consecutive Omori's swarms of earthquakes. We give an analytical proof of the numerical results of an earlier paper [cond-mat/0212529, Mega et al., Phys. Rev. Lett. 90 (2003) 188501] 
L. Palatella, P. Allegrini, P. Grigolini, V. Latora, M.S.Mega, A.   Rapisarda, S. Vinciguerra