The text for the Vulsini, Cimino, Vico and Colli Albani volcanic areas are translated from de Rita (1993), the most comprehensive work on these areas to date.
Vulsini Volcanic Complex
Panoramic view of the Vulsini volcanotectonic depression, filled with marvellous Lago di Bolsena. View is from Montefiascone to the NW, on 5 March 1994. Two small islands, Martana (left) and Bisentina (right) lie in the southern central area of the lake, formed by post-caldera lacustrine eruptions. Historic records indicate that eruptive activity of Vulsini volcano occurred as recently as 104 BC, but geologic evidence exists only for eruptions until about 150 ka ago.
Simplified geologic map of the Vulsini volcanic complex, showing Lago di Bolsena and other volcanic features next to it, among which the Latera caldera and the Montefiascone caldera (on the NW AND SE sides of Lago di Bolsena, respectively) are the most important ones. Taken from De Rita (1993).
The Vulsini Volcanic Complex is the northernmost of the volcanic districts in Lazio. Its activity has been of areal character and been principally explosive. The main structural element is the vast basin of Lago di Bolsena which is interpreted as a volcanotectonic depression that has formed during successive phases of subsidence. This subsidence has been controlled by regional fault systems.
The activity of the complex has occurred from four main eruptive centers that lie on the margins of the main depression, probably along the main tectonic lines of weakness. Activity probably initiated about 0.8 Ma ago from regional fissural eruptive centers ("areal volcanism") in the E part of the complex, and led to the construction of scoria cones and effusion of lava flows.
About 0.6 Ma ago, the activity concentrated at a center now denominated "Paleovulsini" of which nor morphologic traces remain but that may have been present in the area now occupied by the depression of Lago di Bolsena. The oldest volcanic products that crop out in the E and S parts of the lake basin are referred to this period.
Another important eruptive center then grew immediately near the suggested Paleovulsini center and is called "Bolsena-Orvieto". Voluminous air-fall deposits with considerable thicknesses and an ignimbrite called "Bagnoregio Tuff" or "Orvieto Ignimbrite" stem from this eruptive center. The responsable eruption probably occurred 370 ka ago and likely triggered the collapse of the Bolsena Caldera which is located in the NE part of the present volcanotectonic depression.
Contemporaneously with the Bolsena-orvieto center, another center named "Montefiascone" was active on the SE margin of the lake basin, at the site now occupied by the town of Montefiascone. The Montefiascone center had a complex eruptive history including the production of several ash flow units, airfall deposits and violent hydromagmatic eruptions during a period spanning 300 to 150 ka.
Close up view of Isola Martana (center), a youthful post-caldera cone in the SW part of Lago di Bolsena. Isola Bisentina lies in the background immediately to the left; apparently part of its volcanic cone has been destroyed by erosion. View is from the SW shore of Lago di Bolsena, 5 March 1994.
The area of Viterbo, a beautiful city lying between Vulsini, Cimino and Vico volcanoes, has several areas of continuing "post-volcanic" activity, i.e. fumaroles, hot springs and mudpots. This is a pond with a central area of boiling water. Unfortunately, many persons used to drop thir garbage in these beautiful natural attractions, causing the construction of the ugly fence around. Garbage is still being dropped in the channel of the outlet (in the foreground), beyound the fence. This is one really annoying aspect of Italian society. - Photo taken on 5 March 1994.
Drainage system constructed during the Roman time, to divert water from the host springs at the nothern margin of Viterbo to bath ponds. Carbonate has precipitated from overflowing water on the walls of the aquaeduct, forming beautiful miniature sinter basins. Taken 5 March 1994.
Mudponds at the Bulicame hot springs, a few km north of Viterbo (visible in the background, before the skyline of the Cimino-Vico complex). They are a popular resort, very similar to the mudpond at Vulcano island, and people are taking baths at any time of the year (photo was taken on 5 March 1994).
Monte Cimino, a Pleistocene lava dome complex near the town of Viterbo (north of Roma), seen from the village of Vitorchiano, 4 March 1994. This volcanic complex produced a voluminous ignimbrite sheet locally known as "Peperino", a very hard material well suitable for building.
View from the northern outskirts of Viterbo over the city towards the voclanic complex of Monte Cimino, 5 March 1994. Part of the large edifice of the Vico caldera volcano is visible to the right.
The caldera of the Vico volcano, south of Viterbo (Lazio) and adjacent to Monte Cimino (above). Part of the pittoresque caldera lake and the intracaldera cone of Monte Venere carrying a light dusting of snow are visible in this winter image, taken on 2 January 1995. The caldera collapsed some 150 ka ago, and the last activity of Monte Venere took place some 95 ka ago.
Geological map of Vico volcano and its products, taken from De Rita (1993).
View down into the northern part of Vico caldera, on 7 March 1994, from the NW. The youthful post-caldera cone Monte Venere is visible in the center. Note the sharp outline of lava flows at its base.
Sunset over Lago di Vico on 7 March 1994. View is to the W, showing high W rim of the caldera (the remainder of the pre-caldera strato-volcano on whose E flank the caldera was eccentrically formed), called Monte Fogliano.
Etruscan tombs are abundant in the Viterbo region. These are near the village of Barbarano Romano, a few km south of the Vico caldera, cut into the ignibrites of the cataclysmic, caldera-forming eruptions from that volcano. Taken on 28 December 1994.
(image will appear soon)
The Colli Albani (Alban Hills) are seen here from the southern outskirts of Roma, March 1992. Monte Cavo forms what appears to be a central cone (which, in fact, is only a high crater rim). Since the photo was taken, tens of private television antenna have been deployed on the summit (there were less than 10 in March 1992). Colli Albani most recently erupted about 22,000 years ago, forming the craters now filled by the beautiful lakes of Albano and Nemi. The area is still seismically active, as demonstrated again on 12-13 June 1995 when Roma was jolted by a series of earthquakes (up to magnitude 3.9 Richter). In fact, some are fearing a re-activation of the Colli Albani (see a June 1995 newspaper report).
View from Castelgandolfo (the famous residence town of the pope) over Lago Albano, the more northwesterly of the two crater lakes. Monte Cavo (949 m) forms the skyline in the background. Taken on 27 December 1994, view is to the E.
Less known but more suggestive, Lago di Nemi is the youngest of the eruptive centers in the Colli Albani (a phreatomagmatic eruption produced small-volume surge deposits about 22 ka ago). The picturesque town of Nemi lies on the N rim of the crater, offering a commanding view of the lake. This view, taken on 27 December 1994, is from the W side of the crater, looking E.
Lying somewhat far away from classical tourist areas, Roccamonfina, south of the town of Cassino, is being visited much less than the volcanoes shown before. It is, however, being vigorously studied geologically. This view, taken in March 1993, shows the volcano from the W (near Sessa Aurunca). The caldera wall with its highest point on the left side is well distinguishable, the post-caldera lava dome of Monte Santacroce looming above it. Roccamonfina has been the site of several large-volume, ignimbrite-forning eruptions. More info soon.
De Rita D (1993) Il vulcanismo. In: Società Geologica Italiana (ed) Guide Geologiche Regionali: Lazio. 50-64
De Rita D, Funiciello R, Rossi U and Sposato A (1983) Structure and evolution of the Sacrofano-Baccano Caldera, Sabatini Volcanic Complex, Rome. Journal of Volcanology and Geothermal Research vol 17: 219-236
Back to STROMBOLI home page
Back to BB's volcano home page
Visit Other Volcanoes in Italy and in the World
This page was last modified 17 December 1995
Monte Cimino Volcano
Vico Volcano
Sabatini Volcanic Complex
Colli Albani Volcanic Complex
Roccamonfina Volcano
References
Back to The Eolian Islands page
