STRANGE SEISMIC ATTRACTOR

Different time series were constructed from the data set containing al l the seismic events recorded by the Parkfield network between 1969 an d 1987. These series were analyzed to determine whether there exists a n attractor in the phase space of the dynamical system characterizing seismic activity and to tentatively establish its dimension. The study has yielded ambiguous results. For all time time series analyzed, the dimension of the attractor appears higher than 12 and the correlation function of the seismic time series is undistinguishable from that of a series of random numbers of the same length. The lack of difference between the scaling parameters of two series suggests that, for all p ractical purposes, the seismic time series cannot be discriminated fro m a random series.