Active Italian volcanoes are characterized by a large variability of eruptive mechanisms, from quiet lava effusions to catastrophic ignimbritic eruptions. The impact of volcanic activity, and in particular of explosive activity, is clearly related to the intensity and magnitude of the eruptions, varying from an incidental interference with everyday life up to devastating consequences on civilizations. While the largest events have usually monopolized the interest of volcanologists and historians, the modalities and impact of mid intensity eruptions have not been investigated in so much detail. In addition, the frequency of occurrence of mid intensity eruptions is by far higher than that of the largest events, so making their study of primary importance for the assessment of the impact of volcanic activity on environment and human life.

In this paper, case histories of mid-intensity explosive activity at Mt. Vesuvius, Phlegrean Fields, Mt. Etna and Stromboli are presented in order to introduce and discuss the hazard and impact related to this type of activity.