The island rises in depths which range from 1,100 to 1,200 metres so that the total height of the cone is between 2,026 and 2,126 metres. Its summit, called Serra Vancori (926 metres above sea level) is the remains of an ancient vulcanic crater comprised of andesitic lava. At more than 200 metres below this summit opens the actual active crater, bound to the East and West by towers and two crests, formed by banks of lava, conglomerants and dykes, called Filo del Fuoco on the East and Filo di Baraona on the West.
The four morphological units constituting the island are: the ancient stratum-volcano (Paleostromboli) of Serra Vancori to the South; the Cima (918 m.) five hundred metres North of the first; the present crater with four active mouths, 300 metres North of the Cima
(Neostromboli) and the neck of Strombolicchio which represents a temporary cone.
The Stromboli volcanic apparatus stands between two faults, one with direction SW-NE crossing Lipari and Panarea and the other with direction EW crossing the two underwater uplands which are less than 1000 metres deep west of Stromboli.
In the terrace of the crater one can observe the eruptive openings the number of which varies continuously.
The activity of these consists in the launching of shreds of lava and incandescent slag, accompanied by more or less violent explosions, emission of vapour and lavic out laws. Often the various openings are active at the same time in different ways, but the
manifestation of the volcano consists in the moderates activity of launching of contemporary slag which particularly at
night offers an unforgettable spectacle. This moderate activity, at times, is interrupted by brief but violent explosive phases which sometimes ends in the effusion of magma which runs down the slope of the Sciara del Fuoco. The most remarkable eruptions have
been those of the years 1891, 1907, 1915, 1919, 1930 one of the most terrific, 1936, 1954, 1955, 1956, 1959 and 1966. On 28 February 1955 is recorded an interesting eruption: it was evidently a lateral flow which appeared at the level or a little below the level of the sea in the Sciara del Fuoco.
The lava streams do not present any danger whatsoever for the inhabitants of the island since they flow along the Sciara del Fuoco not being able to deviate in other areas owing to the limiting edges. Many authors in the past, have maintened that Stromboli volcano has never given rise to lavic outflows and they have described it as a volcano of exclusively explosive activity, so much
that, from it that particular activity called "strombolian" has taken its name in volcanic terminology. The records of effusive activity confirm however, that the action of this volcano does not have only explosive character but is also effusive with lavic outf laws which at times are lenghty. The activity of the Stromboli volcano does not differ essentially from that of those with basic magma with normally open conduct and we must therefore maintain that at all times there has been a little apparent effusive activity
together with an explosive one of greater force and therefore more easily noticeable.