UB Geografia d'Europa  
STROMBOLI
Geographical overview

Stromboli is the northernmost of the Aeolian Islands, a group of volcanic islands located between Sicily and the southern part of the Italian mainland. The distance to the Italian mainland is 54 km, while there are 240 km to Naples (Napoli) and 55 km to Sicily. The nearest of the other Aeolian Islands is Panarea, 18 km to the Southwest.

Geographical coordinates: 38° 47' N / 15° 12' E


Map generated using Xerox PARC web site.

Stromboli is a continuously active stratovolcano. The summit is at 924 m.a.s.l. However, the base of the volcano is between 1500 and 2000 m below the sea. The surface area of the island is only 12.6 square kilometres.


 

Population and settlements

There are two settlements on the island: Stromboli in the Northeast and the tiny village of Ginostra in the Southwest. In 1991 the total permanent population of the island was 361. However, during the summer months there are many more residents (tourists, employees of hotels etc). The population had been much bigger during the 19th century (see graph on the left). In 1891 it had reached a maximum of 2716. In the first half of the 20th century a massive emigration took place, both to mainland Italy, and to overseas countries such as the US and Australia. Fishing and agriculture (figs, vine) was most important during last century. Today food production is almost nil, and tourism is the major source of income. Punta Lena, in the Southwest part of the island, was extensively cultivated, but it is now almost abandoned.
 

Climate

The climate on Stromboli is typically mediterranean with fairly hot, dry summers. Most precipitation falls in autumn and winter. The total annual rainfall in Stromboli village is around 570 mm on average.

Since there are no permanent streams and no reliable springs on the island, water has to be collected on roofs and verandes and stored in underground reservoirs. Today the demand for fresh water has grown to such an extent that tankers have to deliver water from the mainland up to several times a week during summertime.

Monthly temperature averages are 12 degrees C in February, the coldest month, and 26 in August, the hottest. Snowfall is rare, even on the mountain, but has been observed.
 
 

GEOLOGICAL EVOLUTION OF STROMBOLI

Stromboli may, to a casual observer, appear as little more than a simple volcanic cone. However, its geological history is more varied and interesting than a fist impression may lead to believe. On the next pages we are going to tell you a brief history of how Stromboli developped into its present shape. At the end you have the option to view the island from various angles and see parts of widely different geological ages.

Our prime source of information was the beautiful map by Jörg Keller et. al («Geological Map of the Island of Stromboli», 1:10'000 - small sections reproduced above and below) and on the complementary publication by I. Hornig-Kjarsgaard et.al. (1993): «Geology, stratigraphy and volcanological evolution of the island of Stromboli, Aeolian arc, Italy» in Acta Vulcanologica, Vol. 3-1993: 21-68.

Graphics used on the following image were developped by Christian Balderer and Daniel Meier at the Kantonsschule Zürcher Unterland (external link), Bülach, Switzerland during a special course  in introductory volcanology.
 


1-2. About 200'000 years ago, Stromboli had not yet reached sea level. However, another volcano was active, whose only remnant today is Strombolicchio, an eroded volcanic neck of basaltic andesitic composition

2-3. About 160'000 y B.P. Stromboli emerged from the sea. This happened in the southermost part of the present island.Strombolicchio was being eroded

3-4. Palaeostromboli I and II:
Lava flows andy pyroclastic deposits build up a stratovolcano. Outcrops from this period exist only in deep erosional ravines in the southermost part of todays island. Dated rock ages: 156'000 to 54'800 ± 9'100 y B.P.

4-5. Palaeostromboli III:
The active centre shifted sligthly to the Northwest and erupted lava and pyroclastics which built up a cone to an altitude of at least 700m above sea level. Dated rock ages 35'000 ± 6'000 y B.P.

5-6. Scari Complex and Vancori volcano:
 The Scari Complex is mainly visible in Scari and SW from there as an up to 50m thick sequence mainly formed by bombs and depositis from lahars and pyroclastic flows (lapilli-tuffs; average age about 34'600 y B.P.). Above this lie the pyroclastics and shoshonitic basalt lava flows of the Vancori period (dated rock ages: 26'000-13'000 y B.P.). At certain times there was a large summit crater or even a caldera. This period ended with the collapse of the entire W- and NW-part of the volcano

6-7. Neo-Stromboli:
Shoshonitic basalt lava flows from an eruptive center north of the present Vancori ridge built up again the W- and NW-part of the volcano (dated rock ages: 13'800 ± 1'900 to 5'600 ± 3'300 y B.P.). Secondary eruptive centers led to the formation of the small shield «Timpone del Fuoco» in Ginostra and lava flows in San Bartolo (visible as black cliffs along the beaches!) and in San Vincenzo

7-8. Present Sciara volcano:
Between 10'000 and 5'000 y B.P. the NW slope of Stromboli collapsed again. The landslide left behind a horseshoe shaped depression in the summit area and its deposits can be found in the sea NW of the island to a depth of 2000m. Pyroclastic material and lava flows then re-built this section of the volcano and they also cover the summit area of Pizzo. Recent ash deposits are also found in all terrain depressions on the S-, E- (Rina Grande) and NE side of Stromboli. However, these are not shown in the map
 

Fuente:
STROMBOLI ON-LINE
http://stromboli.net



Última actualització: 7 d'agost de 2000