Transcript Mt. Vesuvius

Mt. Vesuvius
Alicia DiMarco
Kelly Keish
Rebecca Rogers
Activity
Where is it?
Where…
 Italy
– Bay of Naples
 Southwest of Rome
 Pompeii
 Herculaneum
 40.821 degrees North, 14.426 degrees East
Known Eruptions of Vesuvius
 3750 BC
79 AD
472 AD
512 AD
1631 AD
 Vesuvius has been dormant since 1944, but
is believed to be a cyclical volcano where
each centuries long cycle ends in a large
eruption like in 79 AD.
Statistics of Vesuvius
 1281 meters at the summit
 VEI (Volcanic Explosivity Index)
– Rating of 6 on a scale from 0-8
 This means it is 1,000,000 more explosive than a
volcano with a rating of 0
Geology of Vesuvius
 Composite Volcano
– Eruption types
 ash and cinders
 Lava
 Tephrite rock
– Basaltic rocks
 calcic plagioclase, augite, and nepheline or leucite
minerals
Geology of Vesuvius…
 How it formed
– Plate tectonics
 Plates grind against each
other
– Earthquake or Volcano
 Volcano: one plate is
thrust deep into the
Earth, melted into
magma and rises to form
a volcano
– Magma less dense
than solid rock
 The African plate is
being pushed under
the Eurasian plate.
August 24, 79 A.D.
 Ash and Cinders Eruption
 Began as steam discharges in the morning
 Early afternoon: fine ash and pumice fragments formed an “eruptive
cloud”
– Debris begins to fall onto Pompeii and many residents evacuated the city
(pumice fragments as big as 2”)
– Accumulated at the rate of 5-6” per hour
 Many people were still alive at this point
 AUGUST 25 am…
– 2000 people who had survived the pumice showers were killed by ashladen gases
 Suffocation as cause of death…bodies became cemented by ash and rain
 16,000 people ultimately died in Herculaneum and Pompeii
Pliny the Younger
 Roman Soldier who witnessed the eruption and tried to
help those escaping by sea
 An example from his writings
– "Now the day begins, with a still hesitant and almost lazy dawn. All
around us buildings are shaken. We are in the open, but it is only a
small area and we are afraid, nay certain, that there will be a
collapse. We decided to leave the town finally; a dazed crowd
follows us, preferring our plan to their own (this is what passes for
wisdom in a panic). Their numbers are so large that they slow our
departure, and then sweep us along. We stopped once we had left
the buildings behind us. Many strange things happened to us
there, and we had much to fear." (Radice, B., 1968, The Letters of
Younger Pliny: New York, Penguin. )
Pyroclastic Flows
 “A ground-hugging avalanche of hot ash, pumice,
rock fragments, and volcanic gas that rushes
down the side of a volcano as fast as 100 km/hour
or more. The temperature within a pyroclastic flow
may be greater than 500° C, sufficient to burn and
carbonize wood. Once deposited, the ash, pumice,
and rock fragments may deform (flatten) and weld
together because of the intense heat and the
weight of the overlying material.” (US Geological
Survey)
Pompeii
 Located about 6 miles from
Vesuvius
 Rediscovered in 1748
 2000 of the 20,000 inhabitants
were killed
 Many actually died from the gas
expelled from the Volcano rather
than the ash and cinders
themselves
 Fossils (molds and casts)
– When the people were buried in
3m of ash, groundwater
dissolved their bodies over the
next seventeen centuries to
result in these fossils which
maintained the shape of their
bodies, but no internal qualities
Herculaneum
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Located at the foot of Mt. Vesuvius
Rediscovered in the 18th century
Buried by 50-60 feet of pyroclastic material
4 minutes for it to reach and bury
Herculaneum
– 60 FEET OF MUD IN TOTAL THAT ACTED
LIKE CONCRETE
Future Eruptions
 Predictions can be made by:
– Studying the eruptive history
– Monitoring underlying seismic activity
 Frequency and distribution of underlying earthquakes
 Though Vesuvius has
been dormant for 60
years, it is still an
active volcano.
Sources
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simplethinking.com/italy/ pompeii.shtml
http://www.agnr.umd.edu/users/hort/sullivan/21monitor/07/img002.JPG
(http://www.harcourtschool.com/activity/pompeii/pmpKind.html)
http://www.harcourtschool.com/activity/pompeii/pmpErup.html
http://www.pbs.org/wgbh/nova/vesuvius/deadliest2.html
http://www.geocities.com/vesuvius79ad/
US Geological Survey
http://www.roman-empire.net/articles/article-011.html
Earth Science 10th Edition (Tarbuck & Lutgens)- our text!
http://www.bbc.co.uk/history/ancient/romans/pompeii_portents_01.shtm
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