Like all volcanoes Etna has formed over the millennia through a process of construction and destruction began around 600,000 years ago, during the Quaternary. In its place it is believed there was a wide gulf in the point of contact between the sod euro-Asian and north African plate to the south, corresponding to the chain of the Peloritani mountains to the north and to the south the plateau Ibleo. It was the colossal friction between the two plates to give birth to the first submarine eruptions of basaltic lava. Smoothly with the birth of the first volcanic cones, in the middle of the gulf primordial said pre-Etna. It is believed that between 200 and 100.000 years ago these cones entered a new phase of eruptive activity emitting lava otherwise, alkali-basalt.
It was recently documented a huge landslide that fell towards the Ionian Sea around 8000 BC, demolishing about a tenth of the summit cone of the volcano, causing a huge tsunami to the Eastern Mediterranean and Southeast Asia. The Strait of Messina would instead done as a barrier to the tsunami to the western Mediterranean. It is still unclear whether the landslide was caused by an eruption or an earthquake.
The longest eruption in historical memory was on July, 1614. The phenomenon lasted ten years and made more than a billion cubic meters of lava, covering 21 Km square area on the northern slope of the volcano. The flows originated at 2550 and then emerge much further downstream to the height of 975m above sea level, above the towns anyway. In 1669 there was the most famous and destructive eruption, which reached and surpassed, by the side west, the city of Catania; it destroyed the outside to the walls, surrounding the Ursino Castle, which stood on a rocky outcrop stretched the sea, and overcoming it created more than a kilometer of new land. The eruption was heralded by a tremendous roar and an earthquake that destroyed the town of Nicolosi and damaged Trecastagni, Pedara, Mascalucia and Gravina. Then it opened a huge crack from the summit area and, above Nicolosi, began to issue huge amounts of lava. The gigantic lava front advanced inexorably burying Malpasso Mompilieri, Camporotondo, San Pietro Clarenza, San Giovanni Galermo (now part of the city) and Misterbianco well as smaller villages heading towards the sea. They formed the two pyroclastic cones that are now called Monti Rossi, north of Nicolosi. The eruption lasted 122 days and gave a volume of lava about 950 million cubic meters. In 1892 another eruption led to the formation, at approximately 1,800 meters above sea level, the complex of the Monti Silvestri.
The 1983 year is memorable not only for the duration of the eruption, 131 days, with 100 million cubic meters of lava emitted (which destroyed sports facilities and again the cable car), also for the first time in the world of deviation by means of explosives of the lava flow.
On 14 December 1991 began the longest eruption of the twentieth century (lasting 473 days), with the opening of a fracture eruptive crater at the base of South-east, to quotas by 3100 but 2400 m above sea level in the direction of the Valle del Bove. The extensive lava field covered the area called Trifoglietto and headed for the jump mare, who overcame 25 December 1991 toward the Val Calanna. The situation was considered dangerous for the city of Zafferana and was put in place, a strategy of containment arrangement between the Civil Defense and the Army Engineers.
Following are listed some books of 19th century about the activity of guides on Etna:
- "A trip on Etna" by Orazio Silvestri
- Preface and Index of the book with an ancient map of Etna
- "The scientific activity of Prof. Orazio Silvestri in Catania from 1865 to 1887" by Antonio Patanè
Thanks to Mr. Silvestri Pierluigi for him donation to our Cultural Association