to common belief, Mount 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.
Etna seen from the northwest. This view, taken from near
the village of Maletto, shows the snow-clad edifice of the youngest
structural unit of Etna, Mongibello. The cone visible at left is
Monte Maletto, one of about 250 flank eruptive centers on the volcano.
Right: Etna from SSW and the 1669 eruption.
Outcrop in the southwestern part of the 1669 lava flow, near the
town of Misterbianco. The flow was erupted from a large flank cone,
Monti Rossi, which is visible in the far right; this cone lies about
15 km from Etna's summit (visible in the left center). The major
cone visible immediately to the right of the snow-covered summit
area is Montagnola, a crater formed in 1763.
Flank cones near Nicolosi. The southern and southeastern
flanks are dotted with cinder cones produced by flank eruptions, some
of which occurred during historic times. This view is from the summit
of Monti Rossi (the main 1669 cinder cone), on the northwestern margin
of Nicolosi, and shows five cones. The cone visible in the upper left
center (it has three peaks) is Monte Arso, formed in the 15th century.
Right: Montagnola, a cone formed in 1763.
The second of two flank eruptions in 1763 occurred on the upper southern
rim of the Valle del Bove and built a large cinder cone named Montagnola.
This eruption produced an unusually thick lava flow-field which can
be seen as a ridge extending from the Montagnola crater to the right
margin of the photo.
Views of Montagnola from near the main summit cone. The
views were taken from the summit of the "Observatory Cone"
formed in 1971, lookking south. Left: The view during summer (September
1989). Right: Same view taken during the winter (April 1990). Note
black lava flows extending from the foreground to near the base of
Montagnola; most of these were erupted in 1971, but the right photo
shows a very dark lava flow at left which is from the September 1989
eruptions of SE Crater.
from different directions, the shape of Etna shows striking variations,
as can be seen on clear days during a roundtrip in the Circumetnea train
or by car. From southeast, the view is more or less in line with the main
axis of the Valle del Bove, and differs considerably from the Catania
perspective. Here, until the summer of 2001, the mountain appeared quite
symmetrical, culminating with the summit crater complex, and with two
prominent peaks rising to the south and north, forming a peculiar pair
of "shoulders" on the mountain sides. These are the Montagnola
to the south and the Pizzi Deneri, which lie on the westernmost extensions
of the south and north rims of the Valle del Bove, respectively. The 2001
and 2002-2003 eruptions have brought significant changes to this panorama.
Three large pyroclastic cones were formed between the summit cones and
the Montagnola and are plainly visible from southeast, and the shape of
the volcano now appears much less symmetrical.
Seen from Catania to the SSE, the volcano appears fairly symmetrical in
its upper portion but further downslope to the east the symmetry is broken
by the irregular rims of the Valle del Bove, which culminate in the Pizzi
Deneri to the north. Furthermore, the Montagnola, a large cone formed
during a flank eruption in 1763, constitutes a prominent peak below the
summit craters. The sizeable pyroclastic cones formed during the 2001
and 2002-2003 eruptions are now additional features on the upper south
If the volcano is viewed from different places along the highway leading
from Catania to Adrano to the northwest, its shape becomes increasingly
asymmetrical, as the peak of the Montagnola begins to stand more and more
to the right of the steep upper slopes and summit area - the gently sloping
area that lay between the summit and the Montagnola until 2001 was known
as the Piano del Lago (plain of the lake) and now hosts the three large
cones formed during the 2001 and 2002-2003 eruptions. To the left (west),
the rounded upper west flank gradually evolves into a fairly steep slope,
whose base transforms into a gently sloping terrain dotted with numerous
flank cones. Between Adrano and Bronte, further to the north on the west
side of Etna, the shape of the volcano once more becomes more symmetrical
as the irregular morphology of the Piano del Lago-Montagnola area disappears
from view. Seen from west, the mountain essentially shows three main morphological
units: the broad, bulky summit crater complex at the top, followed below
by the steep upper western flank that is lined by numerous dark lava flows
(many of these were erupted during an eruption at the Bocca Nuova summit
crater in 1999). The lower portion of this flank is much flatter and densely
forested; dozens of flank cones of different sizes and ages sit on this
slope, of which the most recent two were formed in 1974.
Continuing the clockwise round trip from Bronte to Randazzo, the shape
of Etna returns asymmetrical, with the upper west flank (now seen to the
right) appearing once more rounded, while the northeastern flank to the
left forms a gently sloping, straight line starting shortly below the
Northeast Crater, which now dominates the summit outline. Flank cones
are much less abundant on this side, but the voluminous lava flow-field
of the 1614-1624 flank eruption becomes apparent, which consists of various
terraces and rootless lava shields (formed around ephemeral vents at the
ends of lava tubes). Eastward from Randazzo along the Alcantara river,
the shape of the volcano once more turns symmetrical, but details begin
to emerge on the Northeast Rift, which forms the slope to the left and
consists of numerous cones and craters of different size and shape. The
most prominent of these is Monte Nero, which formed during a flank eruption
in 1646-1647. As the town of Linguaglossa is approached, the northeastern
(left) flank of the mountain begins to show different elements. Below
the summit craters to the left now appears the crest of the Serra delle
Concazze that culminates at right in the Pizzi Deneri and constitutes
the south rim of the Valle del Bove lying behind. The slope below the
Serra delle Concazze is steep and cut by numerous valleys, some possibly
of glacial origin. Below that slope, the flank of the volcano is sloping
more regularly but is abruptly interrupted by the prominent ridge constituted
by the Northeast Rift, where the large cone of Monte Nero is the most
Near Linguaglossa, the steep symmetrical cone of the Southeast Crater
appears to the left of the summit, which still dominates the summit area
of the volcano, and as the descent toward Piedimonte and then Fiumefreddo
is made, the mountain once more obtains a highly asymmetrical shape. The
irregular crest of the Serra delle Concazze to the left (east) is now
visible over its full extent, while the right flank is dominated by the
Northeast Rift. Driving south along the Ionian coast, the wide opening
of the Valle del Bove becomes more and more evident, with its southern
and northern crests forming irregular ridges. Higher upslope, the cones
of the 2001 and 2002-2003 eruptions return to the view, until the roundtrip
arrives to the north of Acireale, where the perspective is again in line
with the long axis of the Valle del Bove.
section includes two further pages where specific aspects of the Etnean
morphology are discussed in more detail:
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.
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
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.
dominates the skyline of the city of Catania (in the foreground) in this
photo taken from a ship off the Ionian coast in June 1997