Etna

See also: Etna (homonymy)

The Etna (also known under the name of Sicilian Muncibeddu in ) is a Italian Volcan located on the east coast of the Sicily, above the town of Catane. It is the most active volcano of Europe (it currently culminates to 3351 m), and one of the most active volcanos of the world. It covers a surface of 1570 km2 and its perimeter is approximately 200 km. The appearance of Etna goes back to 300000 years, which in fact a recent volcano in geological time .

It is a very complex structure, formed by several juxtaposed successive volcanos: north Is, the South Is, Voragine and Bocca Nuova. The sides of the upper part offer a landscape of ashes and lava flows.

During the 20th century, its altitude frequently varied in a fork of 100 meters, according to castings of Lave and mud. The eruption the most recent date of September 2007.

Its high altitude implies that there exists on its slopes a wet Microclimat which contrasts with the Climat of the sicilian area: fertile Agriculture, stations of Ski, etc One finds there also eternal snow which owes their perenniality with the layers of ashes which recover them (and thus protect them from the solar radiation) more than with altitude, even high, of the mountain (the average altitude of the eternal snow being, in the latitudes of Sicily, higher several hundreds of meters in the summit meeting of Etna).

Etna in Antiquity

Myth

Etna draws its name from the Greek word Aitho , which means which burns . It is also in the Greek Mythologie the name of Ætna , sicilian nymph girl of Ouranos. The legendary origin of the volcano is related to the Gigantomachie. The giant Encelade having deserted the battle field, the goddess Athéna crushes it by projecting on him the island of Sicily where there remains imprisoned. The lava flows of the volcano correspond to its breath of fire; it causes Séisme S of origin volcanic when it is turned over. Greek mythology locates in addition the forging mills of the god Héphaïstos under Etna. It manufactures there the weapons of the gods of the Olympe (the three-pronged fork of Poséidon, the lightning of Zeus, etc) with the assistance of the Cyclops S blacksmiths - not to confuse them with the cyclops pastors, such as Polyphème, which also lived in Sicily. The deaf noises which escape from the volcano are due to the hammering of the tools on the anvils.

The Romans thought that Vulcan was in the island éponyme, of the north of Sicily.

According to the Greek poet Pindare, Zeus fought then locked up the monster Typhon under Etna ( Pythiques , I, 15 sq.), from which it causes the eruptions. It is kept by Héphaïstos. Typhoon carried wings of eagle and had hundred heads of dragon of which the eyes throw flames, as fingers. He is the father of Cerbère and the Chimère. Pindare indicates Etna like the “column of the sky” ( Pythiques , I, 19).

History

This young volcano is located on a zone of friction between the tectonic plates of Europe and Africa.

The first recognized rise of the volcano was made by the Greek philosopher Empédocle between 490 and 430 av. J. - C. the history says that one found his sandals at the edge of the crater. At that time, one threw objects out of gold and silver as offerings with the god Vulcan. If the volcano recrachait them, that meant that he refused them and the giver was then precipitated in the lava.

The Greek geographer Strabon (death towards 23) is one of the first to describe the aspect of Etna seriously. In its work entitled Geography (Book VI, chapter II, 8), it shows the staging of the vegetation and the activities on the slopes of the volcano. It indicates that the top frequently changes form and describes the upper part as having a circular form of 20 [[stage (unit) stages]] of circumference (either approximately 3.6 km).

Holy Agathe, owner of Catane to the foot of Etna, was martyrisée by the Romans into 251. Its death was accompanied by an earthquake which shook all the city. One year after these events, Etna entered in eruption, pouring a flood of lava in direction of Catane. The inhabitants seized the veil which recovered the burial of Agathe and placed it in front of the fire which stopped at once, thus saving the city. Since, one calls upon holy Agathe to protect oneself from the earthquakes, the volcanic eruptions or the fires.

Staging of the vegetation

  • Up to 800 meters: plantations of lemon trees and orange trees
  • Between 1000 and 1500 meters: forests and brooms
  • Above 1500 meters: little vegetation

Geological history

Construction of the volcano

After a prelude related to the volcanicity of the plate hybléen (Monti Iblei) to the south-east of the Sicily, the history of Etna is generally cut out in 4 phases:
  • the period pre-etnaenne (which begins approximately 500000 years ago) whose products is mainly underwater. The famous reefs of Acicastello, to 10 km in the north of Catane, composed of pillow lavas are remainders.
  • the phase old Etna (there is: 168000 ±: 10000  years) where the eruptions are located, for example with Paterno in the South-western South.
  • the phase Trifoglietto II (80000 years ago), construction of a chain of Stratovolcan S successive which pile up.
  • the phase Mongibello (35000 years ago), phase in which we are still. She sees the growth of the Stratovolcan Mongibello in three stages: Old, recent and modern Mongibello. The Valle del Bove, broad notch of 5 km × 7 km, was formed following the collapse of large a Caldeira, several thousands of years ago, but its final form seems due to a collapse going back to approximately 3500 years.

Was the growth of the current top of Etna stopped approximately 2000 years ago (122 av. J. - C.?) by the collapse of the Caldeira Piano at the time of a rare explosive episode plinien. This will caldeira of 2.5 km is still visible and its edge culminates to 2900 Mr. the recent activity of Etna is characterized by emissions of lava and a Strombolian activity, with time with others, more explosive periods at the top. Etna threatened the life of more than 3000000 people hanging several eruptions.

Eruptions

  • July-August 2001: 24 days of eruption; the efforts to build walls of protection could limit the damage. Two Swiss tourists died by the lightning.

  • October 23rd 2002: run which destroyed Piano Provenzana.
  • September 2004: run in Valle del Bove.
  • Starting from the July 14th 2006 with 23  h  30: cracks and lava flow to 3050 m on the slope is south-eastern crater.
  • Tuesday September 4th 2007: eruption with rain of ash on the localities around, and a lava flow in Valle del Bove.

For the complete history to see List of the eruptions of Etna.

External bonds

  • Etna, sicilian Volcano of Charles Rivière: current events of Etna
  • Istituto Nazionale di Geofisica E Volcanologia
  • Volcano-passion Site of David Weber on the passion of the volcanos with many photographs on Etna

Sources

  • site of reference on the eruptions of Etna, complete but in English
  • Site Activolcans
  • Acatte Club - recent history and photographs since 1983

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