A STATISTICAL REAPPRAISAL IN THE RELATIONSHIP BETWEEN GLOBAL AND GREEK SEISMIC ACTIVITY

For the period 1917-1987, Greek seismic activity exhibits a very signi ficant positive correlation to the preceding global activity with a ti me-lag of 15 years. It seems that all Greece and the two characteristi c areas in which we have separated it (Greece without Are, and the are a of the Greek seismic Are), follow the global seismic activity but wi th a time-shift of 15 years. Moreover, it seems to exist an intrinsic interaction mechanism between the Greek seismic are and the rest of Gr eece, which may be deduced by their different behavior exhibited when they are correlated with the global activity, as well as from the corr elation between themselves, where a very significant positive correlat ion has been found with a time-lag of 3 years, for Greece without are preceding. A quasi-periodic term of 30-yrs is also observed in these d etailed four seismic time-series. The cross-correlation analysis of se ismic time-series, as shown, is served as a powerful tool to clarify t he complicated space-time pattern of the world wide mosaic of tectonic plate motions. The implications of spring-block model of tectonic pla tes interaction is invoked, considering the earth's rotation rate chan ges as their triggering agent. Particular emphasis is given to the pot ential of such studies in earthquake prediction efforts from local or regional scales to a global scale and vice-versa.