The Plinian eruption of Pomici di Avellino (3,800 years ago), probably occurring after a long period of quiescence, was one of the most violent in the eruptive history of Vesuvius. It generated thick fallout pumice deposits (approximately 50 cm in the vicinity of the city of Avellino) and pyroclastic flow and surge deposits, distributed in a NW direction, over a distance of more than 15 km from the centre of emission.

Numerous archeological remains testify the presence of a flourishing Bronze Age civilisation in the Vesuvian area at the time of the Avellino pumice eruption, and show that the effect on both the environment and human life was considerable.

All the available data indicate that a caldera began to form during this eruption and that the vent of the eruption was situated in what is now the "Piano delle Ginestre", an area about 2 km. to the West of the present crater.