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Mount Vesuvius

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Mount Vesuvius
Highest point
Elevation1,281 m (4,203 ft) Edit this on Wikidata
Prominence1,232 m (4,042 ft) Edit this on Wikidata
This article is about the mountain in Italy. For other uses, see Vesuvius (disambiguation).

Mount Vesuvius (Italian: Monte Vesuvio, Latin: Mons Vesuvius) is a volcano east of Naples, Italy. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting. The only other two such volcanoes in Italy (Etna and Stromboli) are located on islands.

Vesuvius is on the coast of the Bay of Naples, about nine kilometres (six miles) east of Naples and a short distance from the shore. It is conspicuous in the beautiful landscape presented by the Bay of Naples, when seen from the sea, with Naples in the foreground. Vesuvius is best known for its eruption in A.D. 79 that led to the destruction of the Roman cities of Pompeii and Herculaneum. It has erupted many times since and is today regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people now living close to it and its tendency towards explosive eruptions.

Mount Vesuvius was regarded by the Greeks and Romans as being sacred to the hero and demigod Hercules/Heracles, and the town of Herculaneum, built at its base, was named after him.

Origin of the name

There are three theories about the origin of the name Vesuvius:-

Physical appearance

View of the crater wall of Vesuvius, with Naples in the background

Vesuvius is a distinctive "humpbacked" mountain, consisting of a large (Gran Cono) partially encircled by the steep rim of a summit caldera caused by the collapse of an earlier, and originally much higher structure called Monte Somma. The Gran Cono was produced during the eruption of 79. For this reason, the volcano is also called Somma-Vesuvius or Somma-Vesuvio.

The caldera started forming during an eruption around 17000 (or 18,300 ) years ago and was enlarged by later paroxysmal eruptions ending in the one of 79. This structure has given its name to the term "somma volcano", which describes any volcano with a summit caldera surrounding a newer cone.

The height of the main cone has been constantly changed by eruptions but presently is 1,281 m (4,202 ft). Monte Somma is 1,149 m (3,770 ft) high, separated from the main cone by the valley of Atrio di Cavallo, which is some 3 miles (5 km) long. The slopes of the mountain are scarred by lava flows but are heavily vegetated, with scrub at higher altitudes and vineyards lower down. Vesuvius is still regarded as an active volcano, although its current activity produces little more than steam from vents at the bottom of the crater. Vesuvius is a stratovolcano at the convergent boundary where the African Plate is being subducted beneath the Eurasian Plate. Its lava is composed of viscous andesite. Layers of lava, scoriae, ashes, and pumice make up the mountain.

Formation

View of Somma-Vesuvius, from a convent on the Sorrento Peninsula

Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was pushed beneath the latter, becoming pushed deeper into the Earth. The crust material became heated until it melted, forming magma, one kind of liquid rock. Because magma is less dense than the solid rock around it, it became pushed upward, finding a weak place at the Earth's surface. It broke through, producing the volcano.

The volcano is one several which form the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometres to the north west, Mount Epomeo 20 kilometres to the west on the island of Ischia, and several undersea volcanoes to the south. The arc forms the southern end of a larger chain of volcanoes produced by the subduction process described above, which extends northwest along the length of Italy as far as Monte Amiata in Southern Tuscany. Vesuvius is the only one to have erupted within recent history, although some of the others have erupted within the last few hundred years. Many are either extinct or have not erupted for tens of thousands of years.

Eruptions

Vesuvius has erupted many times. The famous eruption in 79 was preceded by numerous others in prehistory, including at least 3 significantly larger ones, the best known being the Avellino eruption around 1800 BC which engulfed several Bronze Age settlements. Since 79, the volcano has also erupted repeatedly, in 172, 203, 222, possibly 303, 379, 472, 512, 536, 685, 787, around 860, around 900, 968, 991, 999, 1006, 1037, 1049, around 1073, 1139, 1150, and there may have been eruptions in 1270, 1347, and 1500. The volcano erupted again in 1631, six times in the 18th century, eight times in the 19th century (notably in 1872), and in 1906, 1929, and 1944. There has been no eruption since 1944, and none of the post-79 eruptions were as large or destructive as it.

The eruptions vary greatly in severity but are characterized by explosive outbursts of the kind dubbed Plinian after Pliny the Younger, the Roman naturalist who observed the 79 eruption, and whose uncle Pliny the Elder possibly fell victim. On occasion, the eruptions have been so large that the whole of southern Europe has been blanketed by ashes; in 472 and 1631, Vesuvian ashes fell on Constantinople (Istanbul), over 1,200 km away. A few times since 1944, landslides in the crater raised clouds of ash dust, which caused false alarms of an eruption.

Before 79

The mountain started forming 25,000 years ago. Although the area has been subject to volcanic activity for at least 400,000 years, the lowest layer of eruption material from the Somma mountain lies on top of the 34,000 year-old Campanian Ignimbrite produced by the Campi Flegrei complex, and was the product of the Cordola plinian eruption 25,000 years ago.

It was then built up by a series of lava flows, with some smaller explosive eruptions interspersed between them. However, the style of eruption changed around 19,000 years ago to a sequence of large explosive plinian eruptions, of which the 79 one was the last. The eruptions are named after the tephra deposits produced by them:

  • The Basal Pumice (Pomici di Base) eruption, 18,300 years ago, VEI 6, was probably the most violent of these eruptions and saw the original formation of the Somma caldera. The eruption was followed by a period of much less violent, lava producing eruptions.
  • The Green Pumice (Pomici Verdoline) eruption, 16,000 years ago, VEI 5.
  • The Mercato eruption (also known as Pomici Gemelle or Ottaviano), 8,000 years ago, VEI 6, followed a smaller explosive eruption around 11,000 years ago (called the Lagno Amendolare eruption).
  • The Avellino eruption (Pomici di Avellino), 3,800 years ago, VEI 6, followed two smaller explosive eruptions around 5,000 years ago. The Avellino eruption vent was apparently 2 km west of the current crater, and the eruption destroyed several Bronze Age settlements. The remarkably well-preserved remains of one were discovered in May 2001 near Nola by Italian archaeologists, with huts, pots, livestock and even the footprints of animals and people, as well as skeletons. The residents had hastily abandoned the village, leaving it to be buried under pumice and ash in much the same way that Pompeii was later preserved. The eruption was larger than the ones of 79 (VEI 5) and 1631 (VEI 4) with pyroclastic surge deposits distributed to the northwest of the vent, the surges travelling as far as 15 km from it, and lie in the area now occupied by Naples.

The volcano then entered a stage of more frequent, but less violent, eruptions until the most recent plinian eruption which destroyed Pompeii.

The last of these may have been in 217 BC. There were earthquakes in Italy during that year and the sun was reported as being dimmed by a haze or dry fog. Plutarch wrote of the sky being on fire near Naples and Silius Italicus mentioned in his epic poem Punica that Vesuvius had thundered and produced flames worthy of Mount Etna in that year, although both authors were writing around 250 years later. Greenland ice core samples of around that period show relatively high acidity, which is assumed to have been caused by atmospheric hydrogen sulfide.

The mountain was then quiet for hundreds of years and was described by Roman writers as having been covered with gardens and vineyards, except at the top which was craggy. Within a large circle of nearly perpendicular cliffs was a flat space large enough for the encampment of the army of the rebel gladiator Spartacus in 73 BC. This area was doubtless a crater. The mountain may have had only one summit at that time, judging by a wall painting, "Bacchus and Vesuvius", found in a Pompeiian house, the House of the Centenary (Casa del Centenario).

Several surviving works written over the 200 years preceding the 79 eruption describe the mountain as having had a volcanic nature, although Pliny the Elder did not depict the mountain in this way in his Naturalis Historia:

  • The Greek historian Strabo (ca 63 BC-24 AD) described the mountain in Book V, Chapter 4 of his Geographica as having a predominantly flat, barren summit covered with sooty, ash-coloured rocks and suggested that it might once have had "craters of fire". He also perceptively suggested that the fertility of the surrounding slopes may be due to volcanic activity, as at Mount Etna.
  • In Book II of De Architectura, the architect Vitruvius (ca 80-70 BC -?) reported that fires had once existed abundantly below the mountain and that it had spouted fire onto the surrounding fields. He went on to describe Pompeiian Pumice as having been burnt from another species of stone.
  • Diodorus Siculus (ca 90 BC – ca 30 BC), another Greek writer, wrote in Book IV of his Bibliotheca Historica that the Campanian plain was called fiery (Phlegrean) because of the mountain, Vesuvius, which had spouted flame like Etna and showed signs of the fire that had burnt in ancient history.

By 79 the area was, as now, densely populated with villages, towns and small cities like Pompeii, and its slopes were covered in vineyards and farms.

Eruption of 79

File:Pompeii the last day 1.jpg
The eruption of Vesuvius in BBC/Discovery Channel's co-production Pompeii.

By the 1st century, Pompeii was only one of a number of towns located around the base of Mount Vesuvius. The area had a substantial population which grew prosperous from the region's renowned agricultural fertility. Many of Pompeii's neighboring communities, most famously Herculaneum, also suffered damage or destruction during the 79 eruption, which is thought to have lasted about 19 hours, in which time the volcano released about 1 cubic mile (4 cubic kilometres) of ash and rock over a wide area to the south and south-east of the crater, with about 3 m (10 ft) of tephra falling on Pompeii. The white ash produced by this eruption is mainly of leucite and phonolite.

Foreshocks

Outbreak of the Vesuvius. Painting by Norwegian painter I.C. Dahl (1826)

The 79 eruption was preceded by a powerful earthquake seventeen years beforehand on 5 February, 62, which caused widespread destruction around the Bay of Naples, and particularly to Pompeii. Some of the damage had still not been repaired when the volcano erupted. However, this may have been a tectonic event rather than one associated with the re-awakening of the volcano.

Another smaller earthquake took place in 64; it was recorded by Suetonius in his biography of Nero, in De Vita Caesarum, and by Tacitus in Book XV of Annales because it took place whilst Nero was in Naples performing for the first time in a public theatre. Suetonius recorded that the emperor continued singing through the earthquake until he had finished his song, whilst Tacitus wrote that the theatre collapsed shortly after being evacuated.

The Romans grew used to minor earth tremors in the region; the writer Pliny the Younger writing that they "were not particularly alarming because they are frequent in Campania". In early August of 79, springs and wells dried up . Small earthquakes started taking place on 20 August, 79 becoming more frequent over the next four days, but the warnings were not recognised (it is worth noting the Romans had no word for volcano, and only a hazy concept of other similar mountains like Mount Etna, home of Vulcan), and on the afternoon of 24 August, a catastrophic eruption of the volcano started. The eruption devastated the region, burying Pompeii and other settlements. By coincidence it was the day after Vulcanalia, the festival of the Roman god of fire.

The Two Plinys

=====Pliny the Younger=====I got king kong in mai arms

Pliny the Elder

I gOt KiNg KoNg In MaI aRmZ

I gOTz KiNgg KoNgg In MaI tRuNK

Later eruptions

File:Vesuvius wright.jpg
An eruption of Vesuvius seen from Portici, by Joseph Wright (ca. 1774-6)

Since the eruption of 79, Vesuvius has erupted around three dozen times. It erupted again in 203, during the lifetime of the historian Cassius Dio. In 472, it ejected such a volume of ash that ashfalls were reported as far away as Constantinople. The eruptions of 512 were so severe that those inhabiting the slopes of Vesuvius were granted exemption from taxes by Theodoric the Great, the Gothic king of Italy. Further eruptions were recorded in 787, 968, 991, 999, 1007 and 1036 with the first recorded lava flows. The volcano became quiescent at the end of the 13th century and in the following years it again became covered with gardens and vineyards as of old. Even the inside of the crater was filled with shrubbery.

Vesuvius entered a new and particularly destructive phase in December 1631, when a major eruption buried many villages under lava flows, killing around 3,000 people. Torrents of boiling water were also ejected, adding to the devastation. Activity thereafter became almost continuous, with relatively severe eruptions occurring in 1660, 1682, 1694, 1698, 1707, 1737, 1760, 1767, 1779, 1794, 1822, 1834, 1839, 1850, 1855, 1861, 1868, 1872, 1906, 1926, 1929, and 1944. The eruption of 1906 was particularly destructive, killing over 100 people and ejecting the most lava ever recorded from a Vesuvian eruption. Its last major eruption as of 2006 came in March 1944, destroying the villages of San Sebastiano al Vesuvio, Massa di Somma, Ottaviano, and part of San Giorgio a Cremano, as well as all 88 planes in a U.S. B-25 bomber group , as World War II continued to rage in Italy.

The volcano has been quiescent ever since. Over the past few centuries, the quiet stages have varied from 18 months to 7½ years, making the current lull in activity the longest in nearly 500 years. While Vesuvius is not thought likely to erupt in the immediate future, the danger posed by future eruptions is seen as very high in the light of the volcano's tendency towards sudden extremely violent explosions and the very dense human population on and around the mountain.

The future

I STILL GOT KING KONG IN MAI ARM

Vesuvius today

The crater of Vesuvius

The area around Vesuvius was officially declared a national park on 5 June 1995. The summit of Vesuvius is open to visitors and there is a small network of paths around the mountain that are maintained by the park authorities on weekends.

There is access by road to within 200 metres of the summit (measured vertically), but thereafter access is on foot only. There is a spiral walkway around the mountain from the road to the crater.

References

  1. "Vesuvius' next eruption". Geotimes. April 2005. Retrieved 2006-12-08.
  2. ^ "Summary of the eruptive history of Mt. Vesuvius". Osservatorio Vesuviano, Italian National Institute of Geophysics and Volcanology. Retrieved 2006-12-08.
  3. "The Pomici Di Base Eruption". Osservatorio Vesuviano, Italian National Institute of Geophysics and Volcanology. Retrieved 2006-12-08.
  4. Vesuvius, Italy, Volcano World
  5. The world's top volcanoes, Scentia
  6. ^ "Vesuvius". Global Volcanism. Retrieved 2006-12-08.
  7. "Definition of somma volcano". Volcano Live. Retrieved 2006-12-11.
  8. ^ "Somma-Vesuvius". Department of Physics, University of Rome. Retrieved 2006-12-08.
  9. "An ancient Bronze Age village (3500 bp) destroyed by the pumice eruption in Avellino (Nola-Campania)". Retrieved 2006-12-08.
  10. "Vesuvius' Next Eruption May Put Metro Naples at Risk - Lesson from Katrina is need to focus on "maximum probable hazard"". State University of New York. Retrieved 2006-12-08.
  11. "Pomici di Avellino eruption". Osservatorio Vesuviano, Italian National Institute of Geophysics and Volcanology. Retrieved 2006-12-08.
  12. Stothers, R.B. (2002). "The case for an eruption of Vesuvius in 217 BC (abstract)". Ancient Hist. Bull. 16: 182–185.
  13. de Boer, Jelle Zeilinga & Sanders, Donald Theodore (2002). Volcanoes in Human History. Princeton University Press. ISBN 0-691-05081-3.{{cite book}}: CS1 maint: multiple names: authors list (link)
  14. Pliny the Elder, The Natural History (eds. John Bostock, M.D., F.R.S., H.T. Riley, Esq., B.A.) (translation)
  15. Strabo: Geography Book V Chapter 4 (translation)
  16. Marcus Vitruvius Pollio: de Architectura, Book II (translation)
  17. Patterns of Reconstruction at Pompeii
  18. AD 79 - Vesuvius explodes, Current Archaeology
  19. Three Decades of Seismic Activity at Mt. Vesuvius: 1972–2000
  20. The Life of Nero, Suetonius, The Lives of the Caesars
  21. The Annals by Publius Cornelius Tacitus - Book 15
  22. Pompeii at the State University of Minnesot's E-museum
  23. "Visiting Pompeii - AD 79 - Vesuvius explodes". Current Archeology. Retrieved 2006-12-08.
  24. Aviation and the effects of Volcano Ash, Federal Aviation Authority
  25. Vesuvius portal website

External links

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