What is Plate Tectonics?
The theory of plate tectonics explains how and why crustal plates move around the Earth. It also explains why the Pacific Ocean has so many volcanoes, large earthquakes and tsunamis. It gives us a basic understanding of how our planet is changing. It explains how mountains form, why crustal plates move and where great earthquakes are likely to strike.
The Formation of Etna
Mount Etna is an unusual volcano in that most of the world's volcanoes occur on constructive and destructive plate boundaries while Etna is formed on a unique boundary between two continental plates, the European and the African plates, which are pushing towards each other due to convection currents in the mantle beneath the Earth's crust, and will eventually eliminate the Mediterranean.
Mount Etna's Plate Tectonics
There are many theories as to why Mount Etna is so active.
Mount Etna, like other Mediterranean volcanoes such as Stromboli and Vesuvius, rests on the subduction boundary where the African tectonic plate is being pushed under the Eurasian plate. Although they appear to be geographically close, Etna is actually quite different from the other volcanoes. It is actually part of a different volcanic arc. Etna, rather than sitting directly on the subduction zone, actually sits just in front of it.
Etna sits on the active fault between the African plate and the Ionian microplate, which are both being subducted together beneath the Eurasian plate. Current evidence suggests that the much lighter Ionian plate may have broken and part of it forced backwards by the much heavier African plate. Magma directly from Earth’s mantle layer is being sucked into the space created by the tilting Ionian slab.
This phenomenon would account for the kinds of lava produced by eruptions of Mount Etna, which resemble the type of lava produced along deep sea trenches where mantle magma is forced through Earth’s crust. Lava from the other volcanoes is the type produced by the melting of existing crust rather than the upwelling of the mantle layer. There are other possible explanations for the unusual activity of Etna, such as existence of a hotspot or a window-like crack in the African plate.
Mount Etna, like other Mediterranean volcanoes such as Stromboli and Vesuvius, rests on the subduction boundary where the African tectonic plate is being pushed under the Eurasian plate. Although they appear to be geographically close, Etna is actually quite different from the other volcanoes. It is actually part of a different volcanic arc. Etna, rather than sitting directly on the subduction zone, actually sits just in front of it.
Etna sits on the active fault between the African plate and the Ionian microplate, which are both being subducted together beneath the Eurasian plate. Current evidence suggests that the much lighter Ionian plate may have broken and part of it forced backwards by the much heavier African plate. Magma directly from Earth’s mantle layer is being sucked into the space created by the tilting Ionian slab.
This phenomenon would account for the kinds of lava produced by eruptions of Mount Etna, which resemble the type of lava produced along deep sea trenches where mantle magma is forced through Earth’s crust. Lava from the other volcanoes is the type produced by the melting of existing crust rather than the upwelling of the mantle layer. There are other possible explanations for the unusual activity of Etna, such as existence of a hotspot or a window-like crack in the African plate.