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| Version | User | Scope of changes |
|---|---|---|
| May 5 2008, 10:47 AM EDT (current) | clemio | 3 words added, 2 words deleted |
| May 5 2008, 8:48 AM EDT | clemio | 7 words added |
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Vesuvius in History
Mt.Mount Vesuvius today stands over 1,200m. It is still active and is actually in two parts - an external crater, Monte Somma and the main cone, Gran Cono, which was produced by the eruption of AD79.The slopes of the mountain bear witness to the many lava flows that have taken place over the centuries.
However, on these apparently hostile slopes vegetation grows abudantly,abundantly, especially on the lower slopes, due to the richness of the fertile soil (the volcanic ash contains high percentages of soil enriching nutrients potassium, calcium and sodium).
Prior to 79 little is known of volcanic activity with the exception of a massive eruption in about 1800 BC. Since then major eruptions have occurred in 203, 472, 512, 685, 787, 968, 1037 and 1139. Between 1139 and 1631 there was relatively little activity.
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| In December 1631 a major eruption buried many villages under lava flows, killing around 3,000 people. Vesuvius then entered a more continuous period of activity with over 20 major eruptions, culmination in the eruption of March, 1944, which destroyed the villages of San Sebastiano al Vesuvio, Massa di Somma, Ottaviano, and part of San Giorgio a Cremano. ..  |  .. Since 1944 Vesuvius has remained ominously quiet for over 60 years. In recent times the quiet periods have only lasted from between 18 months to 7½ years, so the current lack of activity is abnormal. Vesuvius is being constantly monitored for seismic activity and although it is not thought that Vesuvius will erupt in the immediate future, emergency plans have been put in place to evacuate the population living in the areas of greatest risk to pyroclasic flows. The plans assume that Vesuvius would give sufficient warning to allow for the evacuation of over 600,000. The underlying goal is to reduce the time needed to evacuate the area, over the next 20 or 30 years, to two or three days. |
Pyroclastic Flow
Pyroclastic flows are fast-moving currents of hot gas, ash, and rock, which can travel away from the volcano at up to 700 kph. The gas, ash and rock can reach temperatures of up to 1000 degrees Celsius.
The flows normally hug the ground and travel downhill, or spread laterally under gravity.
The photograph opposite is of a pyroclastic flow sweeping down the Mayon Volcano in the Philippines in 1984.
Phlegraean Fields
Vesuvius is not the only sign of vulcanism in the region. The area known as the Phlegraean Fields lies west of Naples.It is a large 13km wide caldera, mostly submerged today. However the caldera does contain the town of Pozzuoli and the crater of Solfatara.
The area round Solfatara has a large number of fumeroles emitting columns of steam and several pools of boiling mud.
Prior to Roman times the Greeks had colonised the area with towns at Cumae as well as Paestum further to the south.
The photograph on the right is from NASA. Pozzuoli is is the centre of the photograph, Cumae was on the south western coastal strip while the naval base of Misenum was on the peninsula to the south.
