The lateral craters are cones of volcanic slag formed during flank or eccentric eruptions of the volcano (not generated by the summit craters) but by eruptive fractures at lower altitudes. Etna has about 250 along its sides and their number is increasing because with each explosive eruption these cones are formed upstream of the lava flow. They are on average about 100 meters high, made up of pyroclastic and incente material (ash, sand, lapilli, tuffs) and can often manifest themselves through the spectacular “button system”, or several cones in succession aligned on the eruptive axis as if they were of the buttons.
From these craters usually the most destructive lava flows for inhabited centers are generated. For example the Monti Rossi di Nicolosi testify to the historic eruption of 1669 which destroyed towns and parts of the city of Catania, down to the sea.
HIKING NOTES: During our excursions on Etna it will be possible to see many recent and ancient craters and climb to the top of some of these craters.