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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
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Mt. Vesuvius Alicia DiMarco Kelly Keish Rebecca Rogers
Where… • Italy • Bay of Naples • Southwest of Rome • Pompeii • Herculaneum • 40.821 degrees North, 14.426 degrees East
Known Eruptions of Vesuvius • 3750 BC79 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
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. Geology of Vesuvius…
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 ash-laden 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 • 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 • 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.shtml