Fractal stochastic point processes are described by power-law statistics, a
nd therefore, are suited to model the time-occurrence sequence of seismic e
vents, that are generally characterized by a time-clustering phenomenon. In
this paper we quantified the temporal clustering in earthquake sequences b
y means of the Fano factor and the Allan factor, that can be used to reveal
the fractality of such processes. These methods are applied to model the f
ractality of the 1983-1997 seismicity of one of the most seismically active
area of southern Apennine Chain (southern Italy), that has shown the prese
nce of temporal clusterization. (C) 2001 Elsevier Science B.V. All rights r
eserved.