In the year of 79 AD, Mount Vesuvius erupted in one of the most catastrophic and famous eruptions of all time. Historians have learned about the eruption from the eyewitness account of Pliny the Younger, a Roman administrator and poet.
Mount Vesuvius spawned a deadly cloud of stones, ash and fumes to a height of 33 km (20.5 mi), spewing molten rock and pulverized pumice at the rate of 1.5 Mt/s, ultimately releasing a hundred thousand times the thermal energy released by the Hiroshima bombing. The towns of Pompeii and Herculaneum were destroyed by pyroclastic flows and the ruins buried under dozens of feet of tephra. An estimated 16,000 people died from the eruption.
The 79 AD eruption was preceded by a powerful earthquake seventeen years beforehand on February 5, AD 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. The deaths of 600 sheep from "tainted air" in the vicinity of Pompeii indicates that the earthquake of 62 may have been related to new activity by Vesuvius
The Romans grew accustomed to minor earth tremors in the region; the writer Pliny the Younger even wrote that they "were not particularly alarming because they are frequent in Campania". Small earthquakes started taking place on 20 August 79 becoming more frequent over the next four days, but the warnings were not recognized.
Reconstructions of the eruption and its effects vary considerably in the details but have the same overall features. The eruption lasted two days. The morning of the first day was perceived as normal by the only eyewitness to leave a surviving document, Pliny the Younger. In the middle of the day an explosion threw up a high-altitude column from which ash began to fall, blanketing the area. Rescues and escapes occurred during this time. At some time in the night or early the next day pyroclastic flows in the close vicinity of the volcano began. Lights were seen on the mountain interpreted as fires. People as far away as Misenum fled for their lives. The flows were rapid-moving, dense and very hot, knocking down wholly or partly all structures in their path, incinerating or suffocating all population remaining there and altering the landscape, including the coastline. These were accompanied by additional light tremors and a mild tsunami in the Bay of Naples. By evening of the second day the eruption was over, leaving only haze in the atmosphere through which the sun shone weakly.
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"Mt Vesuvius 79 AD eruption 3" by MapMaster - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0-2.5-2.0-1.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/Fi...eruption_3.svg
Herculaneum and other cities affected by the eruption of Mount Vesuvius. The black cloud represents the general distribution of ash and cinder. Modern coast lines are shown.
The latest scientific studies of the ash produced by Vesuvius reveals a multi-phase eruption. The initial major explosion produced a column of ash and pumice ranging between 15 and 30 kilometres (49,000 and 98,000 ft) high, which rained on Pompeii to the southeast but not on Herculaneum upwind. The chief energy supporting the column came from the escape of steam superheated by the magma, created from ground water seeping over time into the deep faults of the region.
Subsequently the cloud collapsed as the gases expanded and lost their capability to support their solid contents, releasing it as a pyroclastic surge, which reached Herculaneum but not Pompeii. Additional explosions reinstituted the column. The eruption alternated between Plinian and Peléan six times. Surges 3 and 4 are believed by the authors to have destroyed Pompeii.[38] Surges are identified in the deposits by dune and cross-bedding formations, which are not produced by fallout.
Another study used the magnetic characteristics of over 200 samples of roof-tile and plaster fragments collected around Pompeii to estimate equilibrium temperature of the pyroclastic flow. The magnetic study revealed that on the first day of the eruption a fall of white pumice containing clastic fragments of up to 3 centimetres (1.2 in) fell for several hours. It heated the roof tiles up to 140 °C (284 °F). This period would have been the last opportunity to escape.
The collapse of the Plinian columns on the second day caused pyroclastic density currents (PDCs) that devastated Herculaneum and Pompeii. The depositional temperature of these pyroclastic surges ranged up to 300 °C (572 °F). Any population remaining in structural refuges could not have escaped, as the city was surrounded by gases of incinerating temperatures. The lowest temperatures were in rooms under collapsed roofs. These were as low as 100 °C (212 °F).
The Two Plinys
The only surviving eyewitness account of the event consists of two letters by Pliny the Younger to the historian Tacitus. Pliny the Younger describes, amongst other things, the last days in the life of his uncle, Pliny the Elder. Observing the first volcanic activity from Misenum across the Bay of Naples from the volcano, approximately 35 kilometres (22 mi), the elder Pliny launched a rescue fleet and went himself to the rescue of a personal friend. His nephew declined to join the party. One of the nephew's letters relates what he could discover from witnesses of his uncle's experiences. In a second letter the younger Pliny details his own observations after the departure of his uncle.
The two men saw an extraordinarily dense cloud rising rapidly above the mountain. This cloud and a request by messenger for an evacuation by sea prompted the elder Pliny to order rescue operations in which he sailed away to participate. His nephew attempted to resume a normal life, but that night a tremor awoke him and his mother, prompting them to abandon the house for the courtyard. Further tremors near dawn caused the population to abandon the village and caused wave action in the Bay of Naples.
The early light was obscured by a black cloud through which shone flashes, which Pliny likens to sheet lightning, but more extensive. The cloud obscured Point Misenum near at hand and the island of Capraia (Capri) across the bay. Fearing for their lives, the population began to call to each other and move back from the coast along the road. A rain of ash fell, causing Pliny to shake it off periodically to avoid being buried. Later that same day the ash stopped falling and the sun shone weakly through the cloud, encouraging Pliny and his mother to return to their home and wait for news of Pliny the Elder.
Pliny's uncle Pliny the Elder was in command of the Roman fleet at Misenum, and had meanwhile decided to investigate the phenomenon at close hand in a light vessel. As the ship was preparing to leave the area, a messenger came from his friend Rectina (wife of Bassus) living on the coast near the foot of the volcano explaining that her party could only get away by sea and asking for rescue. Pliny ordered the immediate launching of the fleet galleys to the evacuation of the coast. He continued in his light ship to the rescue of Rectina's party.
He set off across the bay but in the shallows on the other side encountered thick showers of hot cinders, lumps of pumice and pieces of rock. Advised by the helmsman to turn back he stated "Fortune favors the brave" and ordered him to continue on to Stabiae (about 4.5 km from Pompeii).
Pliny the Elder and his party saw flames coming from several parts of the mountain. After staying overnight, the party was driven from the building by an accumulation of material, presumably, tephra, which threatened to block all egress. They woke Pliny, who had been napping and emitting loud snoring. They elected to take to the fields with pillows tied to their heads to protect them from rockfall. They approached the beach again but the wind prevented the ships from leaving. Pliny sat down on a sail that had been spread for him and could not rise even with assistance when his friends departed. Though Pliny the Elder died, his friends ultimately escaped by land.
In the first letter to Tacitus, Pliny the Younger suggested that his uncle's death was due to the reaction of his weak lungs to a cloud of poisonous, sulphurous gas that wafted over the group. However, Stabiae was 16 km from the vent (roughly where the modern town of Castellammare di Stabia is situated) and his companions were apparently unaffected by the fumes, and so it is more likely that the corpulent Pliny died from some other cause, such as a stroke or heart attack. His body was found with no apparent injuries on the next day, after dispersal of the plume.
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"Pompeii&Vesuvius" by Qfl247 (talk) (Transferred by Citypeek/Original uploaded by Qfl247) - I (Qfl247 (talk)) created this work entirely by myself. (Original uploaded on en.wikipedia). Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/Fi...26Vesuvius.JPG
Pompeii, with Vesuvius towering above
Along with Pliny the Elder, the only other noble casualties of the eruption to be known by name were Agrippa (a son of the Jewish princess Drusilla and the procurator Antonius Felix) and his wife.
An estimated 16,000 citizens in the Roman vicinities of Pompeii and Herculaneum perished due to hydrothermal pyroclastic flows. 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 completely 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. In contrast to the victims found at Herculaneum, examination of cloth, frescoes and skeletons show that it is unlikely that high temperatures were a significant cause. 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. No boats have been found, indicating they may have been used for the earlier escape of some of the population. The rest were concentrated in arched chambers at a density of as high as 3 persons per square meter. As only 85 metres (279 ft) of the coast have been excavated, the casualties waiting to be excavated may well be as high as the thousands.
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"Joseph Wright of Derby - Vesuvius from Portici" by Joseph Wright of Derby - Art collection of the Huntington Library in Pasadena, CA. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/Fi...om_Portici.jpg
An eruption of Vesuvius seen from Portici, by Joseph Wright
Since the eruption of 79 AD, 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 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 April 7, 1906 killed over 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 erupted, devastating the city of Naples. Funds were diverted to the reconstruction of Naples, so a new location for the Olympics was required. London was selected for the first time to hold the Games which were held at White City alongside the Franco-British Exhibition, at the time the more noteworthy event. Berlin and Milan were other candidates.
The last major eruption was in March 1944. It destroyed the villages of San Sebastiano al Vesuvio, Massa di Somma, Ottaviano, and part of San Giorgio a Cremano.[54] From March 18 to 23, 1944, lava flows appeared within the rim. There were outflows. Small explosions then occurred until the major explosion took place on March 18, 1944.
At the time of the eruption, the United States Army Air Forces (USAAF) 340th Bombardment Group was based at Pompeii Airfield near Terzigno, Italy, just a few kilometers from the eastern base of the mountain. The tephra and hot ash damaged the fabric control surfaces, the engines, the Plexiglas windshields and the gun turrets of the 340th's B-25 Mitchell medium bombers. Estimates ranged from 78 to 88 aircraft destroyed.
Ash is swept off the wings of an American B-25 Mitchell medium bomber of the 340th Bombardment Group on March 23, 1944 after the eruption of Mount Vesuvius.
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.
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The March 1944 eruption of Vesuvius, by Jack Reinhardt, B-24 tailgunner in the USAAF during World War II
The area around Vesuvius was officially declared a national park on June 5, 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 (660 ft) 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.
