Breath of The Planet

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Breath of The Planet

• Mount Vesuvius
• Kenisa Nunley
• Geology 108
• Professor Anderson

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Mt. Vesuvius

• Mt. Vesuvius is located in Western Italy where
  the Eurasian plate meets the African plate
  creating a subduction zone .

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What type of Volcano is Vesuvius?

• Mt. Vesuvius is a lava dome which is located in a
  much greater and older, eroded volcano called
• Mt. Somma.
• Vesuvius is a composite volcano in a complex
  composed of a strata volcano (Mt. Somma) and a
  younger crater.

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Mt. Vesuvius, a huge volcano is 1,281 meters high.
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The Rim

• Mt. Somma has a rim which resembles the remains
  of a caldera-like structure of a collapsed
  stratovolcano from about 17,000 years ago. The
  old rim is a dark area most noticeable on the
  right above the lava dome.

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Warning Signs

• Many earthquakes prior to eruption
• Seismic activity occurred which interrupted water
  supplies
• A lengthy, muffled roar shook the ground and sent
  an ominous sound through the air
• The smell of sulphur
• Smoke prior to the eruption

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Warning signs

• A particular large earthquake occurred in 62
  A.D., which is believed to be a warning sign and
  a possible cause of the crack in this piece of
  stone work.

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History

• Many of the people in the town of Pompeii felt
  that they could wait out the event and stayed in
  their homes.
• Unbeknownst to the town, Mt. Vesuvius would erupt
  for over 24 hours and for several hours during
  the eruption it poured out ash, pumice, and
  lithics.
• The calamity would cause one man, Seneca, to take
  great notice of this event, documenting it,
  making the eruption of Mt. Vesuvius on August
  24th, 79 A.D. the first volcanic eruption to be
  recorded.
• It is not possible to predict how many people
  living in the city died, but the Romans who were
  accustomed to losing tens of thousands of men in
  battle thought of this calamity as massive.

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The Blast

• Volcanologists use the term Plinian stage" to
  refer to sustained, explosive eruptions which
  generate high altitude eruption columns and
  blanket large areas with ash.

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Plinian Stage

• Mt. Vesuvius shows many of the characteristics
  of a volcano at the Plinian stage, which can
  have eruptions lasting for several hours, even
  days which include vast amounts of material
  cinders, ash, dust and rocks.

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Plinian Stage

• Yet this phase does not show major signs of lava
  destruction.
• It was suspected that ash rose in a 20 mile high
  column.
• When the debris and materials from the air
  finally descends back to earth, it can accumulate
  in immense amounts.

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Plinian Stage

• Lahars began flowing into the city of Herculaneum
  burying and destroying what was in its path.
• 10 feet of debris fell over Pompeii by the end
  of the explosion.
• Certain estimates also conclude that about 1
  cubic mile of ash poured out over a 19 hour time
  period.

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Ash

• The city of Herculaneum fell under 75 feet of ash
  deposited by a pyroclastic flow.
• The pumice-stones mixed with ashes
• Some victims became immobilized in the hot, heavy
  ash

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Pyroclastic Cloud

• The city was hit by several surges of pyroclastic
  cloud which tore through the city destroying what
  little protection the people had.

• These flows went through the city at speeds of
  100mph bringing with it noxious gases and ash.

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The Cloud

• Around midnight the first pyroclastic surges went
  through the town.

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Pyroclastic Cloud

• The pyroclastic surge was so powerful that the
  people and animals still present in the city
  died instantly, literally baked alive by the hot
  surge of air.

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What have Excavators found?

• Excavators have been able to find out much about
  Pompeii in 79 A.D. due to the preservation by the
  ash which covered the area.
• Ovens were found containing loaves of bread
  almost 2000 years old.
• The victims of Vesuvius were killed instantly,
  immortalizing that moment.

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The Victims

• Cavities were left in the ash where their once
  decomposed bodies lie.

• Plaster was used to fill these cavities to
  reconstruct the victims to how they might have
  looked at their death.

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Why the people are in cowering positions

• On many of the plaster casts the limbs are
  pulled in toward the body, in what is described
  as the "pugilistic attitude," as the heat
  contracted all their flexor muscles.

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Tephrite Rock

• Geologists have found tephrite rock in the area
  of Mt. Vesuvius
• Mt. Vesuvius has become known for tephrite rocks
  which has a basaltic character.
• Tephrite rocks contains the following minerals
  calcic plagioclase, augite, and nephline or
  leucite.

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How Often Does it Erupt ?

• Mt. Vesuvius has erupted more than 50 times
  since the eruption in 79 A.D., when it buried
  Pompeii and its sister city, Herculaneum.
• After the destruction which took place upon
  Pompeii the volcano continued to erupt every 100
  years until about 1037 A.D., when it entered a
  600-year period of quiescence.

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What is happening at Mt. Vesuvius now?

• Today approximately 3 million people live in the
  surrounding cities of Mt. Vesuvius.

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What is happening at Mt. Vesuvius now?

• 30,000 Euros has been offered by The Italian
  government to anyone living in one of the 18
  towns who is willing to move out of the immediate
  area of Mt. Vesuvius.
• In the meantime, volcanologists are
  reconstructing the history of Vesuvius to help
  better predict what might happen in the next
  eruption.

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Mount Vesuvius