Mount Vesuvius ( ) is a somma–stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of several volcanoes forming the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera, resulting from the collapse of an earlier, much higher structure.
The eruption of Mount Vesuvius in 79 AD destroyed the Roman cities of Pompeii, Herculaneum, Oplontis, Stabiae and other settlements. The eruption ejected a cloud of stones, ash and volcanic gases to a height of , erupting molten rock and pulverised pumice at the rate of per second. More than 1,000 people are thought to have died in the eruption, though the exact toll is unknown. The only surviving witness account consists of two letters by Pliny the Younger to the historian Tacitus.
Vesuvius has erupted many times since. It is the only volcano on Europe's mainland to have erupted in the last hundred years. It is regarded as one of the most dangerous volcanoes in the world, marked as one of the Decade Volcanoes, because 3,000,000 people live near enough to be affected by an eruption, with at least 600,000 in the danger zone. Eruptions tend to be violent and explosive; these are known as Plinian eruptions.
Etymology 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 , , and . Writers in ancient Greek used or . Many scholars since then have offered an etymology. Given that peoples of varying ethnicity and language occupied Campania during 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 , "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.
Some theories about its origin are:
From Greek = 'not' prefixed to a root from or related to the Greek word = 'I quench', in the sense of 'unquenchable'. From Greek = 'I hurl' and 'violence' → 'hurling violence', , taking advantage of the collateral form. From an Indo-European root, < < , 'shine', 'burn', sense "the one who lightens', through Latin or Oscan. From an Indo-European root = 'hearth' (compare e.g. Vesta)
The Romans regarded Mount Vesuvius as being devoted to Hercules. The historian Diodorus Siculus relates a tradition that Hercules, in the performance of his labours, passed through the country of nearby Cumae on his way to Sicily and found there a place called "the Phlegraean Plain" (, 'fiery'), "from the mountain which of old spouted forth a huge fire [...] the mountain is called Vesuvius".Diodorus Siculus, Bibliotheca historica 4.21.5 = It was inhabited by giant bandits, "the sons of the Earth". With the gods' assistance, he pacified the region and continued. The facts behind the tradition, if any, remain unknown, as does whether was named after it. An epigram by the poet Martial in AD 88 suggests that both Venus, patroness of Pompeii, and Hercules were worshipped in the region devastated by the eruption of 79. re Epigram IV line 44.
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 , or household shrines, surviving from Pompeii. An inscription from CapuaCIL x.1, 3806 = to indicates that he was worshipped as a power of Jupiter; that is, Jupiter Vesuvius.
Topography
Vesuvius is a "humpbacked" peak, consisting 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 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 cliffs forming the northern ridge of Monte Somma's caldera rim reach a maximum height of at Punta Nasone. The summit of the main cone of Vesuvius is above sea level and more than above the long valley of Atrio di Cavallo (the northern floor of Monte Somma's caldera).
The volcano's slopes are scarred by lava flows, while the rest are heavily vegetated, with scrub and forests at higher altitudes and vineyards lower down.
Formation
Vesuvius is a stratovolcano and was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was subducted at a convergent boundary beneath the latter, deeper into the Earth. As the water-saturated sediments of the African oceanic 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 forming the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometres to the north-west, and Ischia, a volcanic island to the west, 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 in 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
Mount Vesuvius has erupted many times. Numerous others preceded the eruption in AD 79 in prehistory, including at least three significantly larger; an example is 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 distinguished 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 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 five years; only Mount Etna has had as many long-duration eruptions in the last 270 years. The two most recent eruptions of Vesuvius (1875–1906 and 1913–1944) each lasted more than 30 years.
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.
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).
Volcanic explosivity index According to the Smithsonian Institution's Global Volcanism Program, Vesuvius has had 54 confirmed eruptions during the Holocene Epoch (the last 11,700 years). A volcanic explosivity index (VEI) has been assigned to all but one of these eruptions.
Before AD 79 Scientific knowledge of the geologic history of Vesuvius comes from core samples taken from a plus borehole on the flanks of the volcano, extending into Mesozoic rock. Cores were dated by potassium–argon and argon–argon dating. The area has been subject to volcanic activity for at least 400,000 years; the lowest layer of eruption material from the Somma caldera lies on top of the 40,000-year‑old Campanian ignimbrite produced by the Campi Flegrei complex. The volcanic complex stands on a large, sedimentary plain. 25,000 years ago: Vesuvius started forming in the Codola Plinian eruption. Vesuvius was then built up by a series of lava flows, with some smaller explosive eruptions interspersed between them. By this time, the volcano was tall, with the summit being east of the current summit. About 19,000 years ago: the style of eruption changed to a sequence of large explosive and caldera-forming Plinian eruptions, of which the AD 79 one was the most recent. The calderas are aligned in a roughly east–west direction, and all contributed to forming present-day's Somma caldera. The eruptions are named after the tephra deposits produced by them, which in turn are named after the place where the deposits were first identified: 18,300 years ago: the Basal Pumice (Pomici di Base) eruption, VEI 6, the original formation of the Somma caldera. The caldera's formation was asymmetric towards the west. The eruption was followed by a period of much less violent, lava-producing eruptions. 16,000 years ago: the Green Pumice (Pomici Verdoline) eruption, VEI 5. Around 11,000 years ago: the Lagno Amendolare eruption, smaller than the Mercato eruption. 8,000 years ago: the Mercato eruption (Pomici di Mercato) – also known as Pomici Gemelle or Pomici Ottaviano, VEI 6. Around 5,000 years ago: two explosive eruptions smaller than the Avellino eruption. 3,800 years ago (19th century BC): the Avellino eruption (Pomici di Avellino), VEI 6; its vent was apparently west of the current crater and the eruption destroyed several Bronze Age settlements of the Apennine culture, including ancient Afragola.Halpin, Danny. "Village found that was preserved by Mount Vesuvius eruption 2,000 years before Pompeii", Talker News, 11 October 2022 Several carbon dates on wood and bones offer a range of possible dates of about 500 years in the mid-2nd millennium BC. In May 2001, near Nola, Italian archaeologists using the technique of filling every cavity with plaster or substitute compound, recovered some remarkably well-preserved forms of perishable objects, such as fence rails, a bucket and especially in the vicinity, thousands of human footprints pointing into the Apennines to the north. The settlement had huts, pots and goats. The residents had hastily abandoned the village, leaving it to be buried under pumice and ash in much the same way that Pompeii and Herculaneum were later preserved. Pyroclastic surge deposits were distributed to the northwest of the vent, travelling as far as from it, and lie up to deep in the area now occupied by Naples.