Identifying seismicity patterns leading flank eruptions at Mt. Etna Volcano during 1981-1996

Seismicity time properties of the Etna Volcano (Italy) are investigated thr ough a systematic pattern recognition analysis. Mean Hypothesis Testing (MH T) has been applied to a long time database of instrumental data recorded f rom 1981 to 1996 to identify relevant correlation among seismic patterns, m ain seismogenic volumes and the eight flank eruptions occured in the same p eriod. Time evolution of the test statistic (T-Ratio), calculated on a temp oral window starting 75 days prior to a volcanic eruption and extending 25 days after, reveals that there is a pattern of seismic activity prior to th e eruptions that can be used as a diagnostic tool as well as a physical mod eling support in eruption forecasting.