Somma-Vesuvius

The volcanic complex of Somma-Vesuvius covers an area of about 150 km2 and has a maximum height of 1281 m a. s. l. It is composed of an older building, the Somma, characterized by a summit caldera formed in several phases, and the more recent Vesuvius, increased within the caldera. The volcanic complex is less than 39,000 years old and has completed the first phase of its activity, dominated by lava flows and low-energy explosions, about 20,000 years ago.
Afterwards the volcano generated 4 Plinian eruptions, preceded by long periods of dormancy, and about 10 explosive events of lower energy. The last Plinian event is the eruption of 79 A.D., which once again modified the caldera of the Somma, within which the recent cone was formed, with the alternation of periods of persistent Strombolian activity and effusive activity. In historical times, the most energetic events were the subplinian eruptions of Pollena (472 A.D.) and of 1631. Vesuvius was characterized by open conduit and obstructed conduit phases.
The first ones were dominated by frequent, explosive-effusive, low-energy eruptions. This type of activity characterized the volcano in the last period, between 1631 and 1944, the date of the last eruption. The phases with obstructed conduits, like the present one, are characterized by the total absence of eruptive activity. During these periods, which in the past have had a very variable duration, the magmatic system is fed again. These periods ended with explosive eruptions of high energy Lavas

The eruption of March 18, 1944 lasted about 10 days, generated lava flows that partially destroyed the villages of Massa di Somma and San Sebastiano al Vesuvio, and explosions that generated deposits of ash and lapilli, spread over a large area, east and south of the volcano.