Volcanic activity at Mt. Etna and possible seismological precursors. In: Proceedings of the International Workshop "Resumed activity in areas of quiescent volcanism: triggers and precursors", Florence 15-17 May 1986

Changes of some seismological para-meters (earthquakes and tremor) in relationship with different eruptive activities at Mt. Etna, are briefly described. Special care is devoted to variations in the rate of seismicity and in the energy (rms) and frequency content of the spectra of volcanic tremor which change significantly before the beginning of flank eruptions. Simultaneous variations of all the three parame-ters analyzed, seem to possess the character of a precursor phenomenon of flank eruptions, while ter-minal eruptions do not show any significant short-term precursor.