MOUNT VESUVIUS. ITALY.

Classification, complex stratovolcano.

Mount Vesuvius is considered to be one of the most dangerous volcanoes in the world because of its proximity to the city of Naples and the surrounding towns on the nearby slopes. The volcano is classed as a complex stratovolcano because its eruptions typically involve explosive eruptions as well as pyroclastic flows.

Geographic location, Southern Italy.

Vesuvius, also called Mount Vesuvius or Italian Vesuvio, active volcano that rises above the Bay of Naples on the plain of Campania in southern Italy. Its western base rests almost upon the bay.

Year, 79 A.D.

At noon on August 24, 79 A.D., it came to an end when the peak of Mount Vesuvius exploded, propelling a 10-mile mushroom cloud of ash and pumice into the stratosphere

Mount Vesuvius is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km east of Naples and a short distance from the shore. It is one of several volcanoes which form the Campanian volcanic arc.

Last eruption: March 1944, Elevation: 1,281 m

Causes.

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.

Vesuvius today.

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.
You can also look around parts of Herculaneum and Pompeii which have been uncovered.

Mount Vesuvius (/vɪˈsuːviəs/ viss-OO-vee-əs; Italian: Vesuvio [veˈzuːvjo, -ˈsuː-]; Neapolitan: ‘O Vesuvio. [o vəˈsuːvjə], also ‘A muntagna or ‘A montagna; Latin: Vesuvius [wɛˈsʊwɪ.ʊs], also Vesevius, Vesvius or Vesbius is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km (5.6 mi) east of Naples and a short distance from the shore. It is one of several volcanoes which form the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera, caused by the collapse of an earlier and originally much higher structure.

Elevation 1,281 m (4,203 ft)  Prominence 1,232 m (4,042 ft)  , Coordinates 40°49′N 14°26′E. Native name Vesuvio  (Italian), O Vesuvio  (Neapolitan).

Age of rock, 25,000 years before present to 1944; age of volcano = c. 17,000 years to present.

Mountain type, Somma stratovolcano

Volcanic arc/belt Campanian volcanic arc

Last eruption, 17 to 23 March 1944.

Climbing procedures. Easiest route, Walk.

The eruption of Mount Vesuvius in AD 79 destroyed the Roman cities of Pompeii, Herculaneum, Oplontis and Stabiae, as well as several other settlements.

The eruption ejected a cloud of stones, ashes and volcanic gases to a height of 33 km (21 mi), erupting molten rock and pulverized pumice at the rate of 6×105 cubic metres (7.8×105 cu yd) per second. More than 1,000 people are thought to have died in the eruption, though the exact toll is unknown. The only surviving eyewitness account of the event consists of two letters by Pliny the Younger to the historian Tacitus.
Vesuvius has erupted many times since and is the only volcano on the European mainland to have erupted within the last hundred years. Today, it is regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living near enough to be affected by an eruption, with 600,000 in the danger zone, making it the most densely populated volcanic region in the world. It has a tendency towards violently explosive eruptions, which are now known as Plinian eruptions.

Mythology.

Vesuvius has a long historic and literary tradition. It was considered a divinity of the Genius type at the time of the eruption of AD 79: it appears under the inscribed name Vesuvius as a serpent in the decorative frescos of many lararia, or household shrines, surviving from Pompeii. An inscription from Capua to IOVI VESVVIO indicates that he was worshipped as a power of Jupiter; that is, Jupiter Vesuvius.
The Romans regarded Mount Vesuvius to be devoted to Hercules. The historian Diodorus Siculus relates a tradition that Hercules, in the performance of his labors, passed through the country of nearby Cumae on his way to Sicily and found there a place called “the Phlegraean Plain” (Φλεγραῖον πεδίον, “plain of fire”), “from a hill which anciently vomited out fire … now called Vesuvius.”

It was inhabited by bandits, “the sons of the Earth,” who were giants. With the assistance of the gods, he pacified the region and went on. The facts behind the tradition, if any, remain unknown, as does whether Herculaneum was named after it. An epigram by the poet Martial in 88 AD suggests that both Venus, patroness of Pompeii, and Hercules were worshipped in the region devastated by the eruption of 79.

Etymology

Vesuvius was a name of the volcano in frequent use by the authors of the late Roman Republic and the early Roman Empire. Its collateral forms were Vesaevus, Vesevus, Vesbius and Vesvius.[14] Writers in ancient Greek used Οὐεσούιον or Οὐεσούιος. Many scholars since then have offered an etymology.

As peoples of varying ethnicity and language occupied Campania in the Roman Iron Age, the etymology depends to a large degree on the presumption of what language was spoken there at the time. Naples was settled by Greeks, as the name Nea-polis, “New City”, testifies. The Oscans, an Italic people, lived in the countryside. The Latins also competed for the occupation of Campania. Etruscan settlements were in the vicinity. Other peoples of unknown provenance are said to have been there at some time by various ancient authors.

Vesuvius is a “humpbacked” peak, consisting of a large cone (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 Mount Somma. The Gran Cono was produced during the A.D. 79 eruption. For this reason, the volcano is also called Somma-Vesuvius or Somma-Vesuvio.

The caldera started forming during an eruption around 17,000–18,000 years ago and was enlarged by later paroxysmal eruptions,ending in the one of AD 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 was 1,281 m (4,203 ft) in 2010.[21] Monte Somma is 1,132 m (3,714 ft) high, separated from the main cone by the valley of Atrio di Cavallo, which is 5 km (3.1 mi) long. The slopes of the volcano are scarred by lava flows, while the rest are heavily vegetated, with scrub and forests at higher altitudes and vineyards lower down.

Vesuvius is still regarded as an active volcano, although its current activity produces little more than sulfur-rich steam from vents at the bottom and walls of the crater. Vesuvius is a stratovolcano at a convergent boundary, where the African Plate is being subducted beneath the Eurasian Plate. Layers of lava, ash, scoria and pumice make up the volcanic peak.

Their mineralogy is variable, but generally silica-undersaturated and rich in potassium, with phonolite produced in the more explosive eruptions (e.g. the eruption in 1631 displaying a complete stratigraphic and petrographic description: phonolite was firstly erupted, followed by a tephritic phonolite and finally a phonolitic tephrite).

Formation.

Description, Italiano: Giorgio Sommer (1834-1914), “Napoli Panorama” (Mergellina). Numero di catalogo: 1167. Description, German-Italian photographer.

FORMATION.

Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was subducted beneath the latter, deeper into the earth.

As the water-saturated sediments of the oceanic African plate were pushed to hotter depths inside the planet, the water boiled off and lowered the melting point of the upper mantle enough to partially melt the rocks.

Because magma is less dense than the solid rock around it, it was pushed upward. Finding a weak spot at the Earth’s surface, it broke through, thus forming the volcano.

The volcano is one of several which form the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometers to the north west, Mount Epomeo, 20 kilometres (12 mi) 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.

1822

Mount Vesuvius has erupted many times. The eruption in AD 79 was preceded by numerous others in prehistory, including at least three significantly larger ones, including the Avellino eruption around 1800 BC which engulfed several Bronze Age settlements. Since AD 79, the volcano has also erupted repeatedly, in 172, 203, 222, possibly in 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 (including 1779 and 1794), eight times in the 19th century (notably in 1872), and in 1906, 1929 and 1944.

There have been no eruptions since 1944, and none of the eruptions after AD 79 were as large or destructive as the Pompeian one.
The eruptions vary greatly in severity but are characterized by explosive outbursts of the kind dubbed Plinian after Pliny the Younger, a Roman writer who published a detailed description of the AD 79 eruption, including his uncle’s death.

On occasion, eruptions from Vesuvius have been so large that the whole of southern Europe has been blanketed by ash; in 472 and 1631, Vesuvian ash fell on Constantinople (Istanbul), over 1,200 kilometres (750 mi) away. A few times since 1944, landslides in the crater have raised clouds of ash dust, raising false alarms of an eruption.
Since 1750, seven of the eruptions of Vesuvius have had durations of more than 5 years, more than any other volcano except Etna.

The two most recent eruptions of Vesuvius (1875–1906 and 1913–1944) lasted more than 30 years each.

CASUALTIES.

Along with Pliny the Elder, the only other noble casualties of the eruption to be known by name were Agrippa (a son of the Herodian Jewish princess Drusilla and the procurator Antonius Felix) and his wife.

By 2003, around 1,044 casts made from impressions of bodies in the ash deposits had been recovered in and around Pompeii, with the scattered bones of another 100. The remains of about 332 bodies have been found at Herculaneum (300 in arched vaults discovered in 1980). What percentage these numbers are of the total dead or the percentage of the dead to the total number at risk remain unknown.
Thirty-eight percent of the 1,044 were found in the ash fall deposits, the majority inside buildings.

These are thought to have been killed mainly by roof collapses, with the smaller number of victims found outside of buildings probably being killed by falling roof slates or by larger rocks thrown out by the volcano. The remaining 62% of remains found at Pompeii were in the pyroclastic surge deposits, and thus were probably killed by them – probably from a combination of suffocation through ash inhalation and blast and debris thrown around. Examination of cloth, frescoes and skeletons shows that, in contrast to the victims found at Herculaneum, it is unlikely that high temperatures were a significant cause of the destruction at Pompeii.

Herculaneum, which was much closer to the crater, was saved from tephra falls by the wind direction, but was buried under 23 metres (75 ft) of material deposited by pyroclastic surges. It is likely that most, or all, of the known victims in this town were killed by the surges.
People caught on the former seashore by the first surge died of thermal shock. The rest were concentrated in arched chambers at a density of as high as 3 persons per square metre. As only 85 metres (279 ft) of the coast have been excavated, further casualties may be discovered.

Later Eruptions From The 3rd to the 19th Centuries.

Eruption of 16 December 1631. Joachim von Sandrart and Matthias Merian in Danckerts Historis, 1642.

Author, Engraving.

Matthäus Merian  (1593–1650). Swiss copperplate engraver and publisher.

After a drawing by,

Joachim von Sandrart  (1606–1688).
German painter, engraver and biographer.

Since the eruption of AD 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 (760 mi.; 1,220 km).

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 moderately filled with shrubbery.

Vesuvius entered a new phase in December 1631, when a major eruption buried many villages under lava flows, killing around 3,000 people. Torrents of lahar were also created, 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.

Eruptions in the 20th Century.

The eruption of 5 April 1906 killed more than 100 people and ejected the most lava ever recorded from a Vesuvian eruption. Italian authorities were preparing to hold the 1908 Summer Olympics when Mount Vesuvius violently erupted, devastating the city of Naples and surrounding comunes. Funds were diverted to reconstructing Naples, and a new site for the Olympics had to be found.

Vesuvius was active from 1913 through 1944, with lava filling the crater and occasional outflows of small amounts of lava.

That eruptive period ended in the major eruption of March 1944, which destroyed the villages of San Sebastiano al Vesuvio, Massa di Somma, and Ottaviano, and part of San Giorgio a Cremano. From 13 to 18 March 1944, activity was confined within the rim. Finally, on 18 March 1944, lava overflowed the rim. Lava flows destroyed nearby villages from 19 March through 22 March. On 24 March, an explosive eruption created an ash plume and a small pyroclastic flow.

In March 1944, the United States Army Air Forces (USAAF) 340th Bombardment Group was based at Pompeii Airfield near Terzigno, Italy, just a few kilometres from the eastern base of the volcano. The tephra and hot ash from multiple days of the eruption damaged the fabric control surfaces, the engines, the Plexiglas windscreens and the gun turrets of the 340th’s B-25 Mitchell medium bombers. Estimates ranged from 78 to 88 aircraft destroyed.

The eruption could be seen from Naples. Different perspectives and the damage caused to the local villages were recorded by USAAF photographers and other personnel based nearer to the volcano.

The area around the volcano is now densely populated.

The government emergency plan for an eruption therefore assumes that the worst case will be an eruption of similar size and type to the 1631 VEI 4 eruption. In this scenario, the slopes of the volcano, extending out to about 7 kilometres (4.3 mi) from the vent, may be exposed to pyroclastic surges sweeping down them, whilst much of the surrounding area could suffer from tephra falls. Because of prevailing winds, towns and cities to the south and east of the volcano are most at risk from this, and it is assumed that tephra accumulation exceeding 100 kilograms per square metre (20 lb/sq ft)—at which point people are at risk from collapsing roofs—may extend out as far as Avellino to the east or Salerno to the south-east. Towards Naples, to the north west, this tephra fall hazard is assumed to extend barely past the slopes of the volcano.

The specific areas actually affected by the ash cloud depend upon the particular circumstances surrounding the eruption.

The plan assumes between two weeks’ and 20 days’ notice of an eruption and foresees the emergency evacuation of 600,000 people, almost entirely comprising all those living in the zona rossa (“red zone”), i.e. at greatest risk from pyroclastic flows. The evacuation, by train, ferry, car, and bus, is planned to take about seven days, and the evacuees would mostly be sent to other parts of the country, rather than to safe areas in the local Campania region, and may have to stay away for several months.

However, the dilemma that would face those implementing the plan is when to start this massive evacuation: If it starts too late, thousands could be killed, whereas if it is started too early, the indicators of an eruption may turn out to be a false alarm. In 1984, 40,000 people were evacuated from the Campi Flegrei area, another volcanic complex near Naples, but no eruption occurred.

Ongoing efforts are being made by the government at various levels (especially of Campania) to reduce the population living in the red zone, by demolishing illegally constructed buildings, establishing a national park around the whole volcano to prevent the future construction of buildings and by offering sufficient financial incentives to people for moving away.

One of the underlying goals is to reduce the time needed to evacuate the area, over the next twenty to thirty years, to two or three days.

The volcano is closely monitored by the Osservatorio Vesuvio in Naples with extensive networks of seismic and gravimetric stations, a combination of a GPS-based geodetic array and satellite-based synthetic aperture radar to measure ground movement and by local surveys and chemical analyses of gases emitted from fumaroles.

All of this is intended to track magma rising underneath the volcano. No magma has been detected within 10 km of the surface, and so the volcano is classified by the Observatory as at a Basic or Green Level.

National Park.

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 volcano that are maintained by the park authorities on weekends. There is access by road to within 200 metres (660 ft) of the summit (measured vertically), but thereafter access is on foot only. There is a spiral walkway around the volcano from the road to the crater.

Funicular

Mount Vesuvius’ first Funicular — a type of vertical transport that uses two opposing, interconnected, rail-guided passenger cars always moving in concert — opened in 1880, subsequently destroyed by the March 1944 eruption.
“Funiculì, Funiculà”, a Neapolitan language song, was written to commemorate the opening of the first funicular on Mount Vesuvius.

Source, Wikipedia. CC BY-SA 3.0 unless otherwise noted