Vulcano, the ancient HierÓ (sacred), Thermessa or Terasia; is a most interesting island due to its volcanic and post-volcanic phenomena. The peculiar characteristic of Vulcano is its plateau, the most vast of the Aeolian islands, formed by lava, banks of tuff and quaternary deposits and furrowed by deep valleys. It is surrounded by undulating and bare hills, which fall towards the sea. On the high slopes of the island the panorama is picturesque and wild: dykes alternate with extensive areas of tuff and sand. The circular tour of Vulcano is a succession of fantastic visions famous for their variety and beauty of scenery.

Geological sketch map of Vulcano island, from Ventura (1994).

  • 1=alluvium and beach deposits
  • 2=pyroclastics and lavas of the Fossa cone
  • 3=Vulcanello pyroclastics
  • 4=Vulcanello lava platform
  • 5=Alighieri pyroclastics and Monte Saraceno lavas
  • 6=ash flow deposits
  • 7=Punta Roja lava flow
  • 8=lavas of the Lentia volcanic complex
  • 9=Spiaggia Lunga and Quadrara pyroclastics
  • 10=lavas and pyroclastics of Monte Luccia, Piano Luccia, Monte Rosso and Sommata
  • 11=oldest products of Caldera del Piano filling (lavas and pyroclastics)
  • 12=South Vulcano lavas and pyroclastics
  • 13=craters
  • 14=Caldera del Piano and Caldera della Fossa rims
The island of Vulcano is formed by three morphological units: the first, to the South is made of several stratum volcanoes - Mount Aria (500 m), Mount Saraceno (481 m) and Mount Luccia (l88 m)- and of the great horseshoe shaped depression gaping to the North-West of Vulcano Piano (330 m); the second in the middle, is constituted by the Caldera of Vulcano, whose central part makes up the Vulcano Fossa. This is deeply cut and is formed by two craters: the Fossa I and 400 m South West from the first, the present crater Fossa II; it has a diameter of about 500 m, a depth of 200 m and gave way to historically known eruptions, characterized by a mainly explosive activity and by numerous lava flows, one of which, the famous obsidian outflow of Pietre Nere expands along the North-West side in proximity of the two temporary craters of higher and lower Forgia Vecchia. The third unit is made up by Vulcanello (123 m) with its three in line craters in direction North-East South-West. This small apparatus ejected several lava outflows which made up the plateau of Vulcanello and Punta del Roveto. Vulcanello is connected to Vulcano by a thin isthmus, about one metre above sea level - submerged by the sea under particularly adverse weather conditions. The main apparatuses of Vulcano (Monte Saraceno, the Fossa, Forgia Vecchia, the Faraglione and Vulcanello) are in line along a fault in direction North-South. The eruptive activity of the Fossa crater was intense, with more or less long intervals, until the beginning of the historical age; Tucidide, towards the end of the 5C BC supplies us with the first information.During the second half of the 4C BC it seems that this volcano has given rise to violent explosive action and during the succeeding centuries we have news of numerous eruptions. Eruptive activities, with character of explosions, took place in 43 A.D. and afterwards in 1444, 1550, 1626, 1727-1739, 1771-1786, 1812-1831, 1873-1879 and 1886-1890. In 1771 there was an intense activity during which there was ejected the riolitic obsidian outflow called Pietre Cotte, which can be seen on the North Western side. The most recent period of activity began on the 3rd August 1888 and ended on 22nd march 1890. During this eruptive phase there was an ejection of antique and contemporary material of large dimensions and the launching of projectiles which were called "bread-crust" bombs. From that time Vulcano has remained in a fumaroles phase which is limited to the cone of the Fossa and to the interior of its crater. From 1913 to 1923, from the fumaroles of the external part of cone, there occurred four abundant ejections of liquid sulphur. Near the large rocks of Porto di Levante one encounters another fumaroles area, between the remains of an ancient volcanic building, for the most part dismantled. In 1915 on the contour of a lava outflow, at Lentia, other fumaroles were formed which were only short-lived.
Also in the three craters funnels of Vulcanello, up to last century, there occurred a solfataric activity, today completely extinguished. In the fumaroles area of Porto di Levante there are interesting phenomena. In certain tracts the ground is covered by a silical-chalk stratum fractured by small openings. At the point of insertion there arise small cones from the top of which the gases escape with a strong hissing sound. In those parts there is an extensive swamp where the mud is often thrown on high by the violently escaping gas. During Summertime the ground is covered by a beautiful and variegated colour. It is due to efflorescence (fumaroles sublimations) of ferrous and aluminium sulphate oozing from the ground. These formations disappear with the rain. Around the rocks and in front of the beach there occurs the typical phenomenon of the gurgling water caused by underwater fumaroles. On the seabed one notices vast deposits of colloidal sulphur in the form of thin flaky filaments which give to the sea a milky aspect. The gas, bursting out, generates numerous bubbles on the surface of the sea. The phenomenon can be seen very well from the height of the rocks when the sea is calm.

At the beginning of the last century, the Borbonic General Nunziante created at Vulcano the industry for the extraction of sulphur and alums with an efficient complex of roads and factories. During the second half of the century, the Scotsman Stevenson bought the entire island and continued the work of his predecessor on rational lines. A mule track penetrated into the large crater chasm, where were also constructed huts in brickwork for the workmen. The last formidable explosion destroyed everything. Near to the port gushes a hot spring called Acqua di Bagno. The therapeutic power of this water is considerable. In the tourist field Vulcano has assumed a first class role.
Vulcanello (124 m), emerged from the sea in 183 B.C. by an underwater eruption, forms a small peninsular and comprises three craters established on an alternation of lava pyroclastic products. In the Eastern part, due to the erosion of the marine and atmospheric agents, one can see an interesting section showing how a volcanic cone is composed: successions of outflows of lava and strata of pyroclastic materials.