Roger Weller, geology instructor
Mount Vesuvius, Destruction and Glory
Vesuvius: Space Shuttle Photograph
Mount Vesuvius stands at 4,202 feet and is located in Italy just east of Naples on the coast of the Bay of Naples. Although there are two other active volcanos in Italy, Vesuvius is the only active volcano located on the European mainland. Mount Vesuvius is notoriously known for its grand explosion in 79 A.D. This explosion was so massive it destroyed the cities of Pompeii, Herculaneum, and many other small towns located near the slope of the volcano. Even though Vesuvius has not erupted since 1944, experts keep a constant eye on the mountain in order to save lives if there is a destructive blow.
The origin of the name ‘Vesuvius’ is not completely known. The Greeks and
Romans believed Vesuvius was a dwelling place for hero and demigod
Hercules/Heracles, and the town of Herculaneum, built on its base, was named
after him too. In mythology, Hercules was the son of Zeus. Zeus was also known
as Ves. Hercules was also known as Vesouvios (Son of Ves). Linguists believe
“Vesouvious” later turned into “Vesuvius.” According to other sources,
Vesuvius came from the Oscan work fesf, which means “smoke” or the
Indo-European root ves, which means “hearth.”
Vesuvius has quite an extended history on this earth. “The oldest dated rock from the volcano is about 300,000 years old. It was collected from a well drilled near the volcano and was probably part of the Somma volcano”
“The Somma Rim is a caldera-like structure formed by the collapse of a stratovolcano about 17,000 years ago” (http://volcano.und.nodak.edu/vwdocs/volc_images/img_vesuvius.html).
After Somma collapsed Vesuvius began to form. Vesuvius is known as a humpbacked mountain due to its large cone partially encircled by the large secondary summit of Monte Somma. “The height of the main cone is constantly modified by eruptions but presently stands at 4,202 feet and Monte Somma is 3,770 feet high, separated from the main cone by the valley of Atrio di Cavallo, which is some three miles long” (http://en.wikipedia.org/wiki/Mount_Vesuvius).
Vesuvius is a stratovolcano/composite volcano. It is made up of layers of lava and ash. These volcanoes usually emit two kinds of eruptions: one, producing mostly ash and cinders, and the other producing lava. Vesuvius has never been known to produce these two eruptions at the same time. The lava from the volcano is composed of andesite and the mountain is constructed from layers of this lava, scoriae, ashes, and pumice. “Vesuvius is a composite volcano at the convert boundary where the African Plate is being, subducted beneath the Eurasian Plate.” (http://en.wikipedia.org/wiki/Mount_Vesuvius). This is known as a subduction zone.
“When plates grind against one another two things can result- earthquakes and volcanoes. Volcanoes begin to form when the rocks of the lower plate get pushed deep into the Earth. There they are heated, until they melt, forming magma. Because magma is less dense then the solid rock around it, it is pushed upward. If this magma finds a weak place at the Earth’s surface, it may break through and form a volcano”
This allows Vesuvius to be not only a dangerous volcano but also extremely susceptible to earthquakes. These earthquakes usually tend to precede a volcanic eruption. The earthquakes usually last many days.
Vesuvius has gone through many major eruptions in recorded history, but
Vesuvius’ most notorious eruption took place on August 24,Th 79 AD.
“The devastating eruption of 79 was preceded by powerful earthquakes in 62 AD
(February 5th) and 64, which caused widespread destruction around the
Bay of Naples. Earth tremors were commonplace in the region. The Romans,
however, were entirely ignorant of the link between earthquakes and volcanism,
and grew used to them” (http://en.wikipedia.org/wiki/Mount_Vesuvius).
On August 24,Th 79 AD the mountain erupted spontaneously and spectacularly. A column of ash, cinders, and rocks erupted from the mountain. The column is estimated to have been over twenty miles tall. No lava flows occurred during that stage. This stage of a volcanic eruption is called the Plinian stage. “It is named after Pliny, a Roman soldier who sailed into the port of Stabiae to try help some of the people fleeing the volcano”
During the Plinian stage Pompeii and Herculaneum and many other towns around Vesuvius were completely destroyed. Citizens of Pompeii had the advantage of distance (Pompeii is almost ten miles away from Vesuvius). People tried to escape by running out of Pompeii. “Most people living in the area probably escaped during the first phase of the eruption” (http://vulcan.fis.uniroma3.it/vesuvio/79_eruptiontext.html).
The end of the eight-hour eruption covered Pompeii in somewhere between eight and ten feet of hot ash and pumice. The town of Herculaneum suffered an even worse fate. Located on the slope of the mountain, Herculaneum was buried under seventy-five feet of ash, as well as pyroclastic flow and mud flows resulting from the next stage of the volcano.
Illustration of Mount Vesuvius from Pompeii on August 25th 79 A.D.
The next stage of the eruption consisted of an extremely hot cloud of steam and mud. This cloud flowed down the side of the mountain and completely covered the town of Herculaneum. It took only four minutes for the boiling mud to flow from Vesuvius to Herculaneum (four miles away). Simultaneously, earthquakes were going on as well as tsunamis.
By the morning of August 26th the eruption had ended. Pompeii alone
had a death toll of around two thousand.
Most people are thought to have died mainly of suffocation by volcanic gas and ashes, and others were found above the pumice-layer within the surge deposit. Their bodies soon decayed inside the hardening pumice and ash. The air space eventually formed a mold and the ash that surrounded the person created an imprint of the body. Herculaneum on the other hand is more of a mystery. The death toll was never accumulated. Only recently due to remains found where the city used to stand, does the story of Herculaneum become clearer.
“Due to lack of
remains found in the town, it had been long thought that the inhabitants had
escaped, but hundreds of skeletons were discovered in the 1980’s in the former
beach-side boatyard where many had taken shelter. Many of the victims and other
organic objects (such as beds and doors) were carbonized by the intense heat,
which reached temperatures of up to 750 degrees. Many of the victims were found
with the tops of their skulls missing- their brains had exploded in the intense
The complete death toll throughout the region is still unknown (Likely to have been close to 10,000). These two major towns were never re-built and remained a mystery until their accidental rediscovery in the 18th century. Not only did the landscape around the mountain change and the cities surrounding the mountain disappear but also the mountain its self went through major changes. The vegetation and life that once lived on the slopes had disappeared.
Since the eruption of 79 A.D. Mount Vesuvius has erupted about 36 times. In 472, Vesuvius had such a grand volcanic explosion that ash falls were reported as far as Constantinople. In December 1631 a massive eruption buried many villages under lava flows, killing 3,000 people. The volcano has gone off twenty times between 1631 and 1944. “The last eruption came in March 1944, destroying the villages of San Sebastiano al Vesuvio, Massa di Somma and part San Giorgio a Cremano as World War II continued to rage in Italy” (http://en.wikipedia.org/wiki/Mount_Vesuvius). The mountain has had no volcanic activity in over sixty years. This is the longest calm period that Vesuvius has had in over 500 years. Now in the 21st century the Italian government keeps a very close eye on the volcano to avoid a disastrous end like their ancestors experienced.
“’Mount Vesuvius stands within the Naples megalopolis of five million inhabitants. Keeping tabs on it is a matter of massive life and death. No volcano on Earth could put as many people in immediate danger. ‘Our Vesuvius is the one to watch out for’, said Giovanni Mecedonio, director of the Vesuvius Observatory, a venerable institution dedicated to keeping tabs on the volcano’s mood. ’Because Vesuvius has not erupted since 1944, the responsibly for Macedonio and his ninety experts is ever more crucial. The longer a volcano sleeps, the more powerful an explosion is likely to be when it awakens, Vesuvius monitors say” (Williams-1-2).
In the 1990’s, the Italian government created a plan for evacuating the slopes of the mountain in case of an emergency. The residents would travel to pre- selected towns by bus. Yet, this course of action is not easy. The 600,000 residents and 18 towns live on the slope of the volcano. The Italian’s have faced many problems in organization the evacuation procedure. The evacuation plan accounts for having at least two week’s notice of an eruption. “Scientists note that the catastrophic 1980 eruption of Mount St. Helens was preceded by only a few hours of turbulence” (Williams 2).
Vesuvius captivates many people around the world. The bodies of Pompeii and the eruption of 79 A.D. is still a major historical fascination, and many documentaries and books have been created on the subject. The unique shape of the volcano with the beauty of Monte Somma surrounding it also adds to the appeal of Vesuvius. It also begs the question of when will Vesuvius finally wake from its 500 year sleep. The wonder and fatal capacity of Vesuvius helps to rate it as one of the most famous volcanoes in the world.
Williams, Daniel Scientists Keep Tabs On Pulse of Mount Vesuvius. Washington Post Foreign Service. Wednesday, October 13th, 2004 Page A12.
Mount Vesuvius. Wikipedia, the free encyclopedia.
The 79 AD Eruption of Vesuvius. Based on a paper by Scandone, Giacomelli, and Gasparini. Journal of Volcanology and Geothermal Research. 1993.
Pompeii: Vesuvius. Harcourt School Publishers.