Italy is one of the countries with the highest number of volcanoes in the world, mainly because of its complex geological history. Starting from Tuscany, in different periods of activity a volcanic chain developed that ends with Vesuvius in the Italian peninsula and with the Aeolian Islands in the sea.
Etna is one of the most studied volcanoes in the world because of its geographic location, which from a geological point of view is rather strange. In fact, the Aeolian Islands, which are only 60 kilometres away, were formed by the subduction of the Ionian Sea plate under the Calabrian crust. The heating of the oceanic crust in subduction leads to the escape of fluids that cause partial fusion of the overlying lithosphere as they rise. The chemical compositions of these systems, defined as volcanic arc-trench, are always very similar across the world.
The magma of Etna, on the other hand, has a very different chemical composition from that of an arc-trench system, since it is much more similar, for example, to the Hawaiian magma.
Therefore, there are no certain answers to the question asked by this study, only different models and theories.
One of the most accredited theories states that the magma of Etna is able to rise through a tectonic window that is formed in the lateral part of the ionic ocean plate in subduction.