Monte Somma
Mount Somma is the remnant of a large volcano, out of which the peak cone of Mount Vesuvius has grown. Currently, Mount Somma appears to be spread in a semicircle around the north and northeast of Vesuvius. Vesuvius’s formation began during the caldera collapse of Mount Somma.
Approaching Mount Somma from the east, four ridges are encountered:
- Cognoli di Trocchia (961 m, 3,153 ft)
- Cognoli di Sant’Anastasia (1,086 m, 3,563 ft)
- Punta del Nasone (1,132 m, 3,714 ft)
- Cognoli di Ottaviano (1,112 m, 3,648 ft)
Lava flows of 1944
In March 1944, a spectacular lava flow interrupted the north outline of the mountain down to the town of San Sebastiano al Vesuvio. A hiking trail (no. 9 in the numbering of the Vesuvius National Park) allows visitors to cross the entire flow at a width of almost 200 metres (660 ft).
Olivella
Olivella is a village just over 400 m (1⁄4 mile) north of Mount Somma, in the territory of the municipality of Sant’Anastasia. It looks like a natural amphitheatre on top of which is located the Olivella spring; a short distance from the outlet is a stone arch that was part of an aqueduct, built in the time of King Ferdinand I to convey water to Naples.
History
The first evidence of volcanic activity in this area dates back to 400,000 years ago, but the first major eruptive phenomenon of some significance occurred about 25,000 years ago: the eruption of the pumice base when the top of the Somma–Vesuvius volcano collapsed forming a caldera, in which was later formed Vesuvius. Today’s Mount Somma is only the caldera on the northern side.