TIME ASSOCIATION BETWEEN SERIES OF GEOPHYSICAL EVENTS

The problem of evaluating the statistical significance of the time association of different series of events, i.e. the correlation between the instants of occurrence, is often encountered in geophysics. It is of paramount importance in all the issues which have an essentially empirical basis, where chance may play a substantial role in affecting the results. Among others, there is the case of assessing the validity of seismic and volcanic precursors. A general procedure is presented together with a practical application to flank eruptive activity and local seismicity of Mount Etna volcano.