Geoscience Reference
In-Depth Information
grapes, a mountain whose lower slopes are covered in vines.
This has generally been interpreted as Vesuvius, the dominating
feature of that landscape, which was particularly fertile on account
of its volcanic soil.
The historian Strabo described Vesuvius before the eruption
changed its shape for ever:
Above these places [Pompeii, Herculaneum] rises Vesuvius,
well cultivated and inhabited all round, except its top, which
is for the most part level and entirely barren, ashy to the
view, displaying cavernous hollows in rocks, which look as
if they had been eaten by fire, so that we may suppose this
spot to have been a volcano formerly, with burning craters,
now extinguished for lack of fuel.4
Vesuvius is one of the most frequently altered mountains
in general knowledge: its largest eruptions have had significant
effects on its height, form and shape at its summit. If it is Vesu-
vius that is represented in the fresco, and it is reasonable to
suppose that it must be, it is shown in its rugged conical form
before the ad 79 explosion, but long after the immense eruption
around 16,000 bc ripped off its top and formed Monte Somma.
The ad 79 eruption lowered what was left of the mountain
and flattened its top, allowing the summit to flux and change,
eruption by eruption, until the most recent event in 1944.
Meanwhile, 270 km (170 miles) to the south, Etna shivered
and shook as Typhon and Enceladus variously scratched them-
selves and writhed unhappily within. There had been a large
eruption of Etna in ad 38-40 that was heard all round Sicily, but
the mountain has only once, in 1669, produced an event quite
as spectacularly violent as Vesuvius in 79. Etna is of a different
formation to Vesuvius, having vents all around its flanks that are
almost constantly in low-level eruption, making it the most
active volcano in Europe.5
For those relatively few people in Europe in the Middle Ages
who knew of their existence, active volcanoes were sources of
natural terror. A volcano is usually visible to residents of its
