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The Eruption of Mt. Vesuvius August 24, AD 79. Why Vesuvius?. Mt. Vesuvius lies on a fault , a break in the earth’s crust between the African and European crustal plates. The Bay of Naples from the Air (notice the size of Mt. Vesuvius). Subduction Zone.
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Why Vesuvius? • Mt. Vesuvius lies on a fault, a break in the earth’s crust between the African and European crustal plates
The Bay of Naples from the Air (notice the size of Mt. Vesuvius)
Subduction Zone • This break results in magma, or molten rock, being forced up to the surface of the earth where one of the plates is being pushed under the other in a process known as subduction
Mt. Vesuvius • Mt. Vesuvius is a stratovolcano, a volcano built up with layers of magma that create steep sides • This structure creates the potential for violent eruptions
Mt. Vesuvius • Mt. Vesuvius had erupted several times in early Roman history, but Romans kept no records of it; • Vesuvius had not erupted since 1800 BC and was building a large magma chamber
Mt. Vesuvius • In 79 AD Vesuvius was simply regarded as a mons that was suitable for grape cultivation because of the rich volcanic soil • Mt. Vesuvius was named for Hercules, son of Zeus (Ves: in Greek Vesuvious would mean “Son of Zeus”)
August 24, 79 AD • Earthquakes were the first sign of Vesuvius’ activity leading up to August 24, 79 AD • The eruption began about 1 pm with a giant column of smoke, ash exploding from the volcano, material (tephra) ejected from the column
August 24, AD 79 • Small light stones called pumice and heavier stones fell out of the sky at over 100 miles per hour • Vesuvius expelled 1 cubic mile of material in 19 hours • The weight of the ash and pumice collapsed roofs
What Vesuvius Might Have Looked Like on the Day of the Eruption
The Perfect Storm • As ash blanketed the sky, a wind blowing across the bay kept it hovering over Pompeii instead of blowing it out to sea • People began to flee to the shore in hopes of escape – but rescue was not coming
The Perfect Storm • Poisonous gases vented from the volcano, the most deadly of which were carbon dioxide and hydrogen chloride • Across the Bay of Naples, in Misenum, a young Pliny with his uncle, Pliny the Elder, watched the growing disaster
Death Comes • The most deadly material came in the form of a pyroclastic flow – a superheated cloud of gas and ash formed from the collapsing column – moving at 60 kph with a temperature over 600̊ F
The Victims of Vesuvius • The eruption ended on August 25th with the final collapse of the eruption column blanketing Pompeii and nearby cities with ash • Approximately 3,000 people were killed
The Victims of Vesuvius • Because their remains were carbonized, their body forms were left in the ash for archaeologists to study in the 20th century – the eruption had both destroyed and saved a town