What appears to be a single, majestic volcanic edifice is actually a very complex volcanic area. The Etna volcano is in fact made up of numerous volcanic edifices, more or less extensive, that have been superimposed over time on an area of about 1,250 square kilometers.

The first eruptive manifestations, the BASE LAVES, of submarine type, occurred about 500,000 years ago within a large gulf. The filling of this gulf, due to the superimposition of the products of the numerous eruptions that occurred over time, and the gradual uplift of this part of eastern Sicily, allowed the formation of volcanic edifices that were no longer submarine.


80,000 to 64,000 years ago), within which it is possible to count at least five secondary eruptive centers (Serra Giannicola Piccola, Trifoglietto II, Zoccolaro, Vavalaci and Belvedere), has long since ceased to be active and is currently almost completely dismantled. In the area where it stood, on the eastern side of Etna, there is now a large depression called Valle del Bove.

This valley, formed over time by the confluence of the numerous caldera collapses suffered by the various secondary eruptive centers at the end of their activity and thus enlarged by erosion, represents a morphological structure of great scientific interest.
In fact, by studying the volcanic products coming out from its steep and high walls (sometimes more than a thousand meters high), it is possible to reconstruct the evolution of the ancient volcano Trifoglietto.

These studies have shown that the eruptive centers of Trifoglietto were all explosive (and therefore more dangerous than the present active volcano) and that during their activity they erupted enormous amounts of slag, lapilli and ash, which today are found in the form of tuffs, mainly on the eastern slope of Etna.
These intense and violent explosive activities and/or the emptying of the reservoir and the feeding fissures were the main causes of the numerous collapses of the summit part of the various volcanic edifices that occurred over time, with the formation of calderas more or less large.


(34,000-0 years before present), which overlapped with its products on the northwestern flank of the ancient Trifoglietto, is the present active volcano.
Secondary eruptive centers have also been recognized at Mongibello, and two eruptive periods have been distinguished in its evolutionary history.
The Old Mongibello period (34,000 – 8,000 years before present), characterized by eruptive centers of explosive type (elliptical and lion), similar to those of Trifoglietto, and the Recent Mongibello period (8,000 – 0 years before present), characterized by almost exclusively effusive centers (Piano volcano and present volcano), which gave rise to extensive lava effusions. Recent Mongibello is currently the highest (3,345 m) and most active volcano in Europe and, in the last twenty years, one of the most active volcanoes in the world. There are currently four active craters on Etna: Central Crater, divided into Voragine and Bocca Nuova, Northeast Crater and Southeast Crater.