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Contrary to common belief, Etna is not a simple shield or strato volcano. Its shape and structure are extremely asymmetric and complex, and a classification of the mountain on a morphological basis is nearly impossible. The reason for this complexity is that Etna did not grow as one single large cone, but as a succession of volcanic edifices most of which suffered partial collapse at least once during their lifetimes, and whose centers shifted from one place to another.
Several calderas can still be discerned morphologically, the most impressive being the huge Valle del Bove (Valley of the oxen) on the eastern side of the volcano whose latest collapse episodes occurred only a few thousand years ago. Etna's morphology is further complicated by the presence of areas with more frequent eruptive activity, like the Northeast Rift which forms a distinct ridge dotted with eruptive cones and cut by numerous gaping fissures. Hundreds of minor pyroclastic cones are scattered all over the flanks of the mountain, some of which appear to be small volcanoes on their own, with edifice heights of several hundred meters, while many others are much smaller, with heights of only a few tens of meters. These were produced by flank eruptions, the most dangerous, and probably the best documented, type of activity at Etna in recent times. At the summit of the volcano stands a complex of large cones which actually host the four summit craters. This peculiar family of craters, which are somehow connected but show a surprising degree of independence from each other, is a relatively recent feature. One hundred years ago, until 1911, there was one single large cone at the summit of Etna, that was truncated by the 500 m-diameter Central Crater. Two new craters, the Northeast and Southeast Craters, formed in 1911 and 1971, respectively, and have since built their own cones which rival the old central summit cone in size and height. In recent years the Southeast Crater has been particularly active and its growing cone now forms a prominent landmark at the summit of Etna. Viewed from south and southeast it actually seems higher than the central summit cone, but this is an effect of perspective; actually the summit of the Southeast Crater cone is still about 20 m lower than the highest point of the volcano.
This section includes two further pages where specific aspects of the Etnean morphology are discussed in more detail: - The Valle del Bove, a huge collapse depression on Etna's eastern flank. Here you will learn about the various hypotheses proposed to explain the origin of the Valle del Bove, including fascinating new findings.
- The cones and craters of Etna. This will get you acquainted with the recent eruptive centers of Etna, on the flanks (where there are hundreds of pyroclastic cones) and the summit craters, which have an eventful history.
On this page there are many photographs depicting various morphological elements of Etna, such as lava flow features, and furthermore you will get a more graphical idea of what, until now, you have only seen in maps or in text descriptions. This chapter is the base of what will eventuarlly develop into "the Virtual Etna", which will allow you to click on any point on an Etna map to see photos and detailed maps of the chosen area.
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Mt Etna Facts 
