Italy's Volcanoes 

Figure 2. All of the volcanoes in Italy. The map shows active and dormant volcanoes.
Photo credit: http://www.volcanodiscovery.com/italy.html

Figure 1. Shows the Plate interaction and the subduction of the oceanic plate.
Photo credit: http://www.cotf.edu/ete/modules/msese/earthsysflr/plates2.html   

Italy is home to Europe’s most active volcanoes and this is because it is located on a convergent boundary. Along the southern coast of Italy the African plate and the Eurasian plate collide, causing one plate to go beneath the other. This forces molten rock or magma upwards and creates a volcano. The photo (Figure 1) illustrates the process known as subduction. The plate-to-plate interaction accounts for most of Italy's Volcanism.

Mt. Vesuvius

There are two different types of volcanoes, mafic and felsic. Because of Italy’s placement on the convergent boundary almost all the volcanoes are a mix of the two, from very explosive to not explosive, just flowing.  The most famous in Italy is Mt. Vesuvius. This volcano, tall and conical or steep in shape, because of the composite layered structure built up from sequential out pouring’s of eruptive material, can be identified from miles away (BBC). The picture is taken more than 36 km from Mt. Vesuvius and yet its shape shows a textbook example of composite volcano. (Figure 3)

Figure 3. Mt. Vesuvius from  Sorrento, Italy. Photo credit:
Saul Hernandez

Composite volcanoes are dangerous because of their violent eruptions. Mt Vesuvius left a grueling record of how catastrophic they can be. In the 79 A.D. eruption the towns of Pompeii and Herculaneum were buried alive after the volcano exploded. The town Pompeii was perfectly preserved in feet upon feet of ash. In some spots more than 30ft thick. The people who died because of suffocation where then covered by the ash. As it began to cool it created perfect cast moldings of the awful event that we can see today. (Figure 4)

Figure 4. The solidified cast molding of a human that was killed in the  79 A.D. eruption
Photo credit: Saul Hernandez

Mt. Etna

Mt Etna, another composite volcano in Italy, is famous, but for different reasons. Etna takes the prize as Europe’s tallest volcano at 10,925ft and most active. (Geology.com) It is located south of Mt. Vesuvius and situated on a different plate boundary. It is not certain due to its activity which type of volcano Etna is. It has been erupting for thousands of years and quite frequently. The variations in its eruptions have some geologist baffled. It can be explosive and powerful (Figure 5), shoving pyroclastic flows down the side of the mountain and also have steady stream lava flows, which in some cases oppose no danger at all. Possible theories for the eruption differences according to Jessica Ball a graduate student at the University of Ney York include, “rifting processes, a hot spot, and intersection of structural breaks in the crust.” (Geology.com) With no exact reason for the difference in eruptions it continues to be a geological spot of interest!

Figure 5. Eruption on Mt. Etna. Photo credit:
http://photography.nationalgeographic.com/photography/enlarge/mt-etna-eruption-photography.html

References:

http://www.bbc.co.uk/science/earth/surface_and_interior/composite_volcano

http://geology.com/volcanoes/etna/