Vulcano seen from Quattrocchi lookout, Lipari
Vulcano volcano, Isole Eolie, Italy
Vulcano seen from Quattrocchi lookout, Lipari
Vulcano volcano, Isole Eolie, Italy
volcano number: 0101-05= (according to Volcanoes of the World, 1994 edition)
summit elevation: 500 m
location: 38.404°N, 14.962°E
"A volcanic hazard exists where there is the potential for loss of life or property as the direct result of volcanic activity. The major effects of all activity at Fossa are confined to within 2 km of the vent. The village of Porto with a population of about 250 inhabitants lies within this zone to the north of the main cone. During the summer the population of this town swells to more than 10,000. It is quite dangerous for a village to be located so close to an active volcano."
Quoted from Frazzetta et al. 1984. Boldface was set by BB.
Photo above: Vulcano, the southernmost island of the Eolie, has given name to all volcanoes in the world. Site of spectacular activity in the Ancient times and through the 19th century, the crater visible in this photo (Gran Cratere or Fossa Grande) has last erupted in 1888-1890. The long repose period since then and the charm of the place has allowed the rapid development of a settlement, merely a cluster of small houses thirty years ago, now an ever-growing accumulation of villas and hotels. Second to Vesuvio, this is Italy's most dangerous volcano due to the presence of this community in a more-than-irrational proximity to the crater.
The Gran Cratere is filling the foreground of this image; behind (and slightly to the right) lies the peninsula of Vulcanello, formed only during the past 2500 years or so; in the central background is the complex island of Lipari with its Monte S. Angelo forming what appears to be the highest point (although that is Monte Chirica, at 602 m). The twinned cones of Salina's Monte dei Porri (left) and Monte Fossa delle Felci form the left skyline. Image was taken from below the highest part of Gran Cratere (391 m) on 18 April 1995.
Geological sketch map of Vulcano island, from Ventura (1994). Click on image for large version and explanation.
Vulcano is seen here from the northwest, with the steaming Gran Cratere in the center and Vulcanello visible to the left. The high peak on the right margin of the image is Monte Saraceno (481), a high part of the oldest, "Piano" stage of Vulcano complex. The photo was taken on 28 August 1991.
Vulcano seen from Monte Guardia (Lipari) on the afternoon of 5 November 1990. Vulcanello forms the peninsula in the foreground of the main Fossa cone. Note white building on the southernmost crest of Lipari, this is the Volcanological Observatory of Lipari maintained by the Consiglio della Ricerca, Italy.
Located on the southernmost of the Aeolian Islands, the active cone of Vulcano has impressed the Ancient Greek and Romans that much that they considered it the home of their underworld divinity, Hephaistos or Vulcanus. Even though as a mountain it is neither very conspicuous nor aesthetically appealing, it is one of Italy's most significant active volcanic centers, mostly due to its high hazard potential.
View from N rim of Fossa crater over the village of Vulcano Porto towards the pensinsula of Vulcanello. Lipari is visible in the central background, Salina at left (with Monte dei Porri at left and Monte Fossa delle Felci at right), Panarea is at the extreme right. Taken on 13 September 1995.
Vulcano has three population centers, the smallest of which is Gelso on the S tip of the island. The village of Piano lies on the stupendous plateau of the same name that constitutes the south-central portion of the island. A complex settlement named Vulcano Porto extends from the immediate N base of the Fossa cone to the isthmus connecting Vulcano with Vulcanello and covers large parts of the Vulcanello peninsula.
Evolution of Vulcano island
The island of Vulcano is geologically complex. Its evolution took place during the past >150 ka and is generally divided into four major stages: South Vulcano center, Lentia volcanic complex, Fossa cone and Vulcanello.
Renewed eruptions began about 15.5 ka ago from eruptive centers in the southern and western parts of the island (Quadrara and Spiaggia Lunga volcanics) as well as in the northwest where the large rhyolitic to trachytic lava dome and flow complex of Lentia was formed. Violent ash-flow forming eruptions occurred from somewhere in the strait between Vulcano and Lipari and deposited brown tuffs over a large area of the Piano caldera. About 15-14 ka ago, another caldera collapse affected the island, this time in its northern part, forming the Fossa caldera.
About 6 ka ago, activity concentrated in the center of the Fossa caldera, leading to the formation of the still-active Fossa cone. Its activity is described below.
The most recent and westernmost crater of Vulcanello seen from its SE rim on 13 September 1995. Part of the Vulcanello lava platform with large villas and hotel and apartment complexes lies below the cone, and parts of Lipari and Salina are visible in the upper right corner of the photo.
Still more recently, a new eruptive center formed in the strait between Vulcano and Lipari. The first recorded eruption occurred 183 or 123 BC and formed a new island. Sporadic eruptions continued until the mid 16th century AD. By that time, the new island had significantly enlarged and eventually connected with the main island of Vulcano. The activity produced a cluster of three overlapping tephra and scoria cones with craters shifting from E to W, and a gently sloping lava platform mainly on the N, W and S sides of the cone cluster. The Vulcanello products are generally more mafic than most other Vulcano eruptives, being of leucite-tephritic composition, only the most recent lava flow (Punta del Roveto) is trachytic.
Suggestive landscape of "Valle dei Mostri" (Valley of the Monsters) on the 16th centruy lava flow of Punta del Roveto (NE of Vulcanello peninsula), early April 1995. Monte Guardia (Lipari) is visible in the background in the center of the photo.
Vulcanello has not erupted during the past 400 years, and fumarolic activity has declined after the mid-19th century. During a visit to the most recent (westernmost) crater on 13 September 1995, I found no evidence of recent hydrothermal activity but I had no sophisticated eqipment with me that might have detected low-temperature emissions.
South Vulcano became active about 120 ka ago and built a large stratovolcano, made up mostly of trachybasaltic to trachyandesitic lava flows. Intercalations of pyroclastic fall and flow deposits constitute only a minor portion of that volcano. Activity of the South Vulcano eruptive center was interrupted about 97 ka ago by the collapse of the 2.5 km diameter Piano Caldera (Caldera del Piano).
Post-caldera activity continued until about 50 ka ago. The earlier of these eruptions came from ring faults and later from eruptive centers aligned along N-S and NE-SW trending fractures. Then, no volcanic activity occurred on the island for more than 30 ka.
Activity continued within the new caldera, producing pyroclastics and lava flows (the most significant being the Punta Roja lava flow that crops out at the E base of the Fossa cone. Eruptions also occurred from N-S trending fissures in the NW part of the older Piano caldera where the Alighieri formation and the edifice of Monte Saraceno were formed.
Map of the northern part of Vulcano island with the eruptive centers of Fossa and Vulcanello (from Frazzetta et al. 1984, slightly modified). Dotted areas are lava flows erupted during the past 15 ka from eruptive centers within the Fossa caldera (but not from Vulcanello). Irregular dots north of Fossa cone and on the Vulcanello peninsula are buildings of Vulcano Porto (as of 1983).
Eruptive history of Fossa cone during the past 6000 years
The evolution of the Fossa cone, the most recently active volcanic center on Vulcano island, has been described in detail by Frazzetta et al. (1983) and briefly reviewed by Frazzetta et al. (1984) and Frazzetta & La Volpe (1991). The following is a summary from those sources.
The Fossa eruptive center developed only during the past 6000 years, after the presumably tectonically triggered formation of the Fossa caldera, about 14-16 ka ago. Its birth followed post-caldera effusive activity of which the 14 ka Punta Roja lava flow gives testimony (see the geological map). Activity of the Fossa cone has been divided into several cycles by Frazzetta et al. (1983, 1984) and Frazzetta & La Volpe (1991) that have generally shown a characteristic succession of eruptive styles and each had an individual eruptive vent. Some cycles began with powerful vent-clearing explosions leading to deposition of "phreatic breccias" near the eruptive vents. The hydromagmatic initial stages of other cycles produced wet and/or dry surge deposits. Later products of each cycle show a decreasing influence of external water, the final products being fully magmatic (pumice-fall deposits or lava flows).
Punte Nere cycle
Palizzi cycle
Commenda cycle
Pietre Cotte cycle
The complete lack of erosional surfaces and paleosoils between the products representing a cycle, it is assumed that activity during each cycle was more or less continuous. This contrasts with distinct erosional unconformities between the products of various cycles, evidence of longer repose periods separating different eruptive cycles.
The initial activity of this first recognized Fossa eruptive cycle was hydromagmatic and produced a >60 m thick sheet of dry surge deposits overlying the Punta Roia lava flows (14±6 ka). The basal strata of this sheet are composed of coarse and fine clasts and are overlain by sandwave and massive beds. Fragments of a trachytic lava flow that may have been ruptured by the eruptions and a thick block-fall deposit are present in the middle part of the sequence. A fall deposit composed of normally bedded and occasional reversely bedded layers with interbedded surge beds make up the uppermost pyroclastic unit of the cycle. It was followed by the emplacement of the trachytic Punte Nere lava flow that forms a delta-like feature on the N base of the Fossa cone. This flow was dated at 5400±1300 years.
Frazzetta & La Volpe (1991) estimate the volume of tephra produced during the Punta Nere cycle at 195 x 10^6 m^3 and that of lava at about 3 x 10^6 m^3. The activity left a cone about 250 m high, its NE crater rim is still well discernible in the eastern part of the Fossa cone.
At least three undefined eruptive cycles occurred after the Punta Nere cycle and left wet and dry surge deposits as well as the Campo Sportivo lava flow (see the map of lava flows), on the NW base of the Fossa cone. That flow has a radiometric age of 4600±1700 years and thus falls into the same time window as the Punta Nere flow; stratigraphically, though, it lies in a higher position. The volume of the Campo Sportivo lava flow is 2.6 x 10^6 m^3 while that of the tephra presumably associated with it is 25 x 10^6 m^3. The volume of tephra from the other undefined cycles is about 10 x 10^6 m^3.
Following a repose period of unknown duration, hydromagmatic activity led to the emplacement of wet surge deposits followed by dry surge beds. Accretionary lapilli in these initial deposits give testimony of a high water component during the opening stage of the cycle. Later activity produced a stratified, normally graded pumice horizon which shows evidence of a brief erosional interval at its top. When activity resumed, it was again hydromagmatic and deposited another set of basal wet and overlying dry surge horizons.
Like during the preceding cycle, the late stage activity was effusive, producing about 0.6 x 10^6 m^3 of trachytic lava that forms a narrow tongue on the S flank of the Fossa cone (Palizzi lava flow, see the map of lava flows). The volume of all tephra emitted during the Palizzi cycle is given as 5 x 10^6 m^3. The age of the Palizzi lava flow is 1600±1000 years. This is well within the historic period but no correlation of the deposits with recorded historic eruptions of Vulcano is possible. The historic eruptions (except the 1888-1890 one) are therefore handled separately on a "VULCANO_elenco.html">different page.
This cycle began with powerful explosive activity of which a basal breccia gives testimony. The breccia is composed of yellow hydrothermally altered clasts and is overlain by a pyroclastic flow unit with numerous fumarolic degassing pipes. The activity then shifted to hydromagmatic and produced wet and then dry surge deposits with abundant Pele's hair (!) before it became again magmatic with the extrusion of the Comenda obsidian lava flow that is still partially visible on the SW flank of Fossa cone (see the map of lava flows). Its volume is 2.6 x 10^6 m^3, slightly more than one tenth of the tephra volume (25 x 10^6 m^3).
Frazzetta et al. (1983) assumed that the upper and larger of the two Forgia Vecchia ("Old Forge") craters was formed during the Comenda eruptive cycle. These craters are well distinguishable on the two photos below of the 1888-1890 eruption but have been subjected to intense erosion since then and are densely vegetated.
The initial activity (breccia and pyroclastic flow) probably occurred before the mid 6th century AD since these deposits are overlain by the white ash from the most recent explosive eruption of Monte Pilato, Lipari that is thought to have occurred around AD 550. The Pilato ash is overlain by the wet and dry surge deposits. Historic documents indicate that the emplacement of the Comenda lava flow may correspond to an eruption recorded for the year AD 785.
Initial activity was hydromagmatic, producing wet surge and soon after, dry surge deposits. A pyroclastic fall sequence (described as "pumice" by Frazzetta and La Volpe 1991) rests on top of these early products. The exact timing of the eruption's beginning is not known but it is probable that one of its more peculiar events, the formation of the lateral Forgia Vecchia II crater (on the NW rim of Forgia Vecchia I crater), occurred in 1727. Twelve years later, lava seems to have filled the main Fossa crater and spilled over its low N rim, forming the obsidian lava tongue of Pietre Cotte ("Cooked Stones") that is still conspicuous on the steep northern slope of the Fossa cone (see the map of lava flows). Its volume is 2.4 x 10^6 m^3.
Unlike other cycles, the Pietre Cotte cycle apparently did not end with the lava outflow. Following the effusive activity, eruptions resumed in 1771 and continued intermittently until 1890. All activity before the latest major eruptive episode, in 1888-1890, is not well documented whereas very detailed scientific descriptions of the most recent activity are available (see below).
Photo of Vulcano in eruption, 14 February 1889. This view is of an explosion that ejects large bombs or blocks above a steam and ash plume. This photo was originally published in Mercalli & Silvestri (1891) and shows evidence of slight editing. Similar eruptions, though on a smaller scale, are common at Stromboli (see the 1993 images by Jon Dehn).
Another view of Vulcano on 14 February 1889, this time during continuous ash emission. Poor quality of this image is due to scanning from a photocopy (the original is in Mercalli & Silvestri 1891. Libraries usually don't let you get out with that book and are even reluctant letting you make copies).
This is the largest of the famous breadcrust bombs ejected during the 1888-1890 eruption from Fosa Grande (the crater visible in the background). Giada Giuntoli is the person who gives scale. This bomb didn't make it far away from the crater, but smaller ones fell abundantly in the area now occupied by the village of Vulcano Porto. 18 April 1995.
1888-1890 eruption
Vulcano last erupted in 1888-1890. Although it had erupted frequently in historic times, this eruption was the only one that was observed by scientists and was described in detail (Mercalli & Silvestri 1891). The activity observed by them was used for the introduction of a new scientific term, the so-called "Vulcanian" style of volcanic activity, now applied for powerful magmatic activity somwhere transitional between Strombolian and sub-Plinian (check the Glossary of Volcano World and "Types of volcanic eruptions" of the Volcano Information Center for more detailed information about these somewhat controversial terms).
The eruption was particular for the ejection of countless large breadcrust bombs. Meter-sized bombs fell in the area now occupied by the village of Vulcano Porto, on the crater rim they are much larger (see the previous photo).
The buildings of the sulfur mining company located at Porto Levante were heavily damaged by falling tephra already during the first days of the eruption (starting on 3 August 1888), their residents could escape without fatalities or injuries. Later eruptions caused occasional ash and rare lapilli falls at Lipari. No major damage was done there, but the area now occupied by the village of Vulcano Porto was subjected to heavy bomb and lapilli showers.
The eruption ended on 22 March 1890, after gradually declining for several days. There were repeated unconfirmed reports about eruptive unrest at or near Vulcano, but no significant eruptive activity took place after 22 March 1890.
With the 1888-1890 eruption, the Pietre Cotte cycle seems to have come to a close. The volume of tephra produced during the entire cycle is given by Frazzetta & La Volpe as 25 x 10^6 m^3 of which the 1888-1890 products do not make up more than one fourth.
One of the major attractions of Vulcano, the hot mudpond on the isthmus between Vulcano and Vulcanello has already been inviting to the Romans. This view is taken from the strongly altered remains of a tuff cone (Faraglione) whose colorful landscape is visible in the foreground, 13 September 1995. Note the building under construction in the background: this is the "Casa Inglese", the house of the owner (an Englishman) of the sulfur mines before the 1888-1890 eruptions of the Fossa volcano. This historic building has for a long time been quite ignored.
This is the place where I saw Giada (my fiancee) for the very first time (on 6 November 1990).
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