Points of Interest
The Volcano
Vesuvius is a characteristic example of a volcano in a volcano made by an
outer broken cone, Mt. Somma, which has an almost completely destroyed
crater belt. In it there is a smaller cone, the Vesuvius, divided from
the former by a depression called Valle del Gigante, a part of the
ancient caldera where subsequently, probably during the 79 AD eruption,
the Gran Cono or Vesuvius arose.
Valle del Gigante is divided into
two parts: Atrio del Cavallo in the west, and Valle dell'Inferno in the east. The northern part of Somma's ancient crater is well preserved,
since it has been protected from the volcano's devastating violence by
the height of the internal wall which prevented the lava from moving
downslope. The slopes are furrowed by deep radial gorges produced by
the erosion of the meteoric waters. The whole section is then
characterized by dark volcanic rock spikes. The old crater edge is
formed by a series of summits called "cognoli".
While the height of mount Somma and its profile have remained unchanged
for centuries, the height and the profile of the Vesuvius have suffered
considerable variations caused by the following eruptions, with
raisings and lowerings.
The Vesuvius is a characteristic polygenic and mixed volcano: this
means that it consists of lava of different chemical composition (for
example trachytes, tephrites, leucitites) and formed both by lava flows
and by pyroclastic deposits. All the areas lying on the mountain slopes
are formed by soils transported by mudflows moving downslope in the
rainy seasons through deep and narrow gorges called beds or more
commonly "lagni". The high embankments are formed by piles of lavic
scoriae, which precipitated in incandescent state and spread towards
the lower slopes, being precious for the vegetation thanks to their
fertile material, rich in silicium and potassium.
History
At the beginning of the Quaternary period (the
second eruptive phase of the Flegrei), an eruption of trachytes gave
origin to the primitive Mt. Somma; it was followed by further eruptions
which took place between 6,000 and 3,000 BC and between 3,000 BC and
the Christian era, causing above all leucitic basalt emissions. Later,
after a long period of rest, the volcanic activity began again with
tremors which preceded, starting from February 5th, 63 AD (the
earthquake described by Seneca), the terrible eruption which took place
on August 24th, 79 AD, during which the three towns of Ercolano,
Pompei, and Stabia were completely destroyed and buried by a thick
blanket of ashes, lapilli, and lava. Some scientists assert that this
eruption, called "Plinian" eruption, gave origin to the present Gran
Cono of the Vesuvius. However, it was the first historically dated and
documented eruption in a famous letter to Tacitus written by Pliny the
Younger, who during the cataclysm lost his uncle Pliny the Elder,
victim of his naturalistic passion. Among the subsequent eruptions, we
remember those of the years 202, 472, 685, 1036, 1139, and the very
violent one of December 16th, 1631 during which most of the villages
situated at the foot of the volcano were destroyed and about 40,000
people died: on this occasion, the lava reached the sea.
The
Vesuvius was active again during the 17th, 18th, and 19th centuries
(1822, 1855, 1858, 1861, 1872). Other eruptions followed, and the
crater profile was completely transformed by them. After the violent
paroxysm of 1906, during which millions of cubic metres of lava were
erupted, a fearful crateric chasm formed in the Gran Cono. The last
eruption took place in March 1944: 21 million cubic metres of lava
erupted, a number of villages were destroyed, and the ashed reached
Albania. Since then, the volcano has no longer erupted, although
frequent seismic phenomena demonstrate that it is a dormant volcano. In
the past, the volcano has been object of careful studies dealing with
the eruption forecasting, studies which are still carried out today and
which do not foresee any sudden awakening. The Volcanological
Observatory belongs not only the history of the volcano, but also to
the world volcanology; it is situated in the observatory zone in the
high part of the Town of Ercolano, within the Park territory. It is
easy to reach it by following the provincial road climbing to the
crater and turning right at the Hotel Eremo. It was built in the 19th
century, and it was the first volcanological observatory in the world,
the place where the first seismic and volcanological researches took
place, and where different instruments of measure were used. Among its
directors there are important scientists such as Palmieri, Melloni, and
Mercalli. It houses a small museum of scientific instruments used in
the past to study earthquakes and volcanoes.
The Park Municipalities
The Municipalities lying at the National Park borders are 13, all within the Province of Naples. The total inhabitants are 361,783 (the reference year is 1996).
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