For other meanings of Etna, see Etna (disambiguation).
Mount Etna (or Aetna, and known locally as Mongibello) is an active volcano on the east coast of Sicily (Italian Sicilia), close to Messina and Catania. It is the largest volcano in Europe, standing about 3,320 m (10,900 ft) high with a basal circumference of 140 km, making it the highest mountain in Italy south of the Alps. Etna covers an area of 460 square miles (1190 kmē). It is by far the largest of the four active volcanos in Italy, being nearly three times the height of the next largest, Mount Vesuvius. It is one of the most active volcanoes in the world and is in an almost constant state of eruption. Although it can occasionally be very destructive, it is not generally regarded as being particularly dangerous.
Name and legends
Etna was known in Roman times as Aetna, a name thought to have derived either from the Greek word aitho ("to burn") or the earlier Phoenician word attano. The Arabs called the mountain Gibel Utlamat ("the mountain of fire"); this name was later corrupted into Mons Gibel and subsequently Etna's current local name Mongibello.
The mountain's regular and often dramatic eruptions made it a major subject of interest for Classical mythologists and their later successors, who sought to explain its behaviour in terms of the various gods and giants of Roman and Greek legend. Aeolus, the king of the winds, was said to have imprisoned the winds in caves below Etna. The giant Typhon was confined under Etna, according to the poet Aeschylus, and was the cause of the mountain's eruptions. Another giant, Enceladus, rebelled against the gods, was killed and was buried under Etna. Hephaestus or Vulcan, the god of fire and the forge, was said to have had his forge under Etna and drove the fire-demon Adranus out from the mountain, while the Cyclopes maintained a smithy there where they fashioned lightning bolts for Zeus to use as a weapon. The Greek underworld, Tartarus, was supposed to be situated beneath Etna. Empedocles, a major pre-Socratic philosopher and Greek statesman of the 5th century BC, was said to have met his death in the volcano's crater, although in reality he seems to have died in Greece. Etna supposedly erupted in sympathy with the martyrdom of Saint Agatha in 251 AD, prompting Christians thereafter to invoke her name against fire and lightning.
Etna is an isolated peak which dominates the eastern side of Sicily, around 18 miles (29 km) from Catania. Its shape is that of a truncated cone with a ragged top, which is actually a complex of large volcanic cones hosting four summit craters. Around 260 smaller craters, formed by lateral eruptions, occupy the slopes. On the southeastern side of Etna lies an immense gully, the Valle del Bove, which is between 2000-4000 ft (600-1200 m) deep and over 3 miles (5 km) wide. Many of Etna's subsidiary craters reside within this cleft, which is thought to have been created around 3,500 years ago by the collapse of an ancient caldera. The height of the mountain varies with its eruptions; until 1911, there was only one large cone and crater at the summit, but subsequent eruptions have created new craters and cones.
The slopes of Etna form three distinct zones. The lower zone, extending up to about 4000 ft (1200 m) are densely populated and planted with vineyards, citrus fruits, and groves of olives, figs and almonds. The middle zone (up to about 6900 ft / 2100 m) is heavily wooded, mostly with pine and chestnut trees. At the top of the mountain is a volcanic wasteland, dominated by old lava flows, screes and volcanic ash. Few plants grow there and it is covered by snow for much of the year.
Classification and morphology
Etna is an extremely complex volcano, presenting considerable difficulties in classifying it. It has features of both a shield volcano and a stratovolcano, and displays behaviour typical of both plinian and strombolian volcanoes. It stands at the convergent boundary where the African Plate is being subducted beneath the Eurasian Plate, deforming the latter and forcing plumes of magma upwards into weak points in the crust such as under Etna. It is perhaps most accurate to describe Etna as being a mixture of overlapping shield and strato volcanoes partially destroyed by repeated collapses and partly buried under subsequent volcanic edifices.
Etna is highly active and erupts almost constantly, although most of the time the eruptions are confined to the summit craters and nearby fissures. Every few years, a major eruption or "outburst" takes place in which spectacular fire fountains appear, often accompanied by flows of lava. As Etnean lava is extremely viscuous and flows at only a few meters or a few tens of meters per hour, the danger to human life is minimal, although the sheer quantity of lava can sometimes lead to considerable destruction of property. The substantial human population of the mountain's slopes and base means that large-scale lava flows can often threaten to overwhelm local settlements.
Only vague records of Etna's ancient eruptions survive. The earliest recorded eruption was that of about 475 BC, recorded by the Greek poet Pindar in his First Pythian Ode of about 470 BC. The Roman poet Virgil gives a very vivid description of an eruption - probably first-hand - in his Aeneid:
- The port capacious, and secure from wind,
- Is to the foot of thund'ring Etna joined.
- By turns a pitchy cloud she rolls on high:
- By turns hot embers from her entrails fly,
- And flakes of mounting flames, that lick the sky.
- Oft from her bowels massy rocks are thrown,
- And shivered by the force come piece-meal down.
- Oft liquid lakes of burning sulphur flow,
- Fed from the fiery springs that boil below."
Etna is known to have erupted over sixty times in recorded history. In 1169 and 1669, immense lava flows descended the flanks of the mountain, reaching the sea and destroying Catania on both occasions. The 1669 eruption saw the creation of a huge rift 20 km long on the mountainside and the emergence of two new volcanic cones, more than 100m high and measuring nearly 3 km in circumference at their base. These hills were named Monti Rossi. In 1928, the town of Mascali was destroyed by lava. Other major 20th century eruptions occurred in 1949, 1971, 1991, and 2000. In 2001-2002, the biggest series of eruptions for many years threw up a huge column of ash that could easily be seen from space and fell as far away as Libya, on the far side of the Mediterranean Sea.