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Byron Guided Excursions
Etna is an extremely complex volcano just
as its subsurface. Under the mountain, the rock layers of the Appennine
chain (which in the table are shown beneath the Peloritan Mountains),overlap
the Ibleian outpost layer, which coincides with the old edge of the
African continent. The whole rests on the continental crust. The picture
also shows the ducts which connect the volcano deep region to several
eruptive mouths. As for the magmatic reservoir which feeds all the
volcanic structure, it is the subject of research by the use of more and
more advanced technologies. On the basis of the latest eruptions of
Etna, today it is supposed the presence of a deep structure more
articulated and varied than it was thought in the past. In particular,
the National Institute of geophysics and volcanology of Catania, has put
forward the hypothesis of the existence of three magmatic reservoirs,
placed between 0 and 13 kilometres below the volcano, where piles up all
the material which will be expelled during the eruption. The first one,
placed at sea-level, in the layer of the Flysch of the Appennine layers,
is probably small sized and connected to the surface through several
ducts which reach the four top craters of Etna. The second one, five
kilometres below the surface, is in the Ibleian outpost and it likely
feeds the previous one which is in an overhanging position. The third
reservoir, 12/13 kilometres below the surface, is in the continental
crust. It is supposed to carry the material to the second reservoir, but
up to now it is not clear how this passing takes place.
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