Saturday, 23 May 2015

Volcanic activity on Mount Etna.

The Osservatorio Etneo at the Istituto Nazionale di Geofisica e Vulcanologia reported the beggining of a new phase of volcanic activity on Mount Etna, an active volcano on the island of Sicily beginning on Tuesday 12 May 2015 with a series of Earth tremors beneath the mountain. At about 4.10 am local time on Wednesday 13 May an east-west fracture appeared beneath the east rim of the volcano's New Southeast Crater, revealing a series of vents, one of which produced a small lava flow. At about 8.00 am the fracture began to spead again, reaching about 200 m from the rim of the cone in under 10 minutes. This was accompanied by further rim collapses and the ejection of a quantity of incandescent ash around the summit of the volcano and down its southern flank.This activity continued till 16 May, though it began to die of on the 15th. Further small lava eruptions ashfalls occured around the south and northeast of the volcano; a lava flow was reported which trended northeast then split in two flowing to the west and east, the western flow reaching 5 km from the vent.

 Flow of lava issuing from Mount Etna on 16 May 2015. Marco Restivo/Barcroft Media.

Etna first erupted about half a million years ago, beneath the sea off the east coast of Sicily, and has been going strong ever since. It now stands 3330 m above sea level, and covers 1200 km³. It is responsible for fertile soils across eastern Sicily. Records of eruptions on Etna go back to 1500 BC. It is Europe's second largest volcano, after Teide in the Canary Islands, and is one of the most active volcanoes in the world.

 The location of Mount Etna. Google Maps.

Despite all this Etna has only ever caused 77 recorded deaths (the most recent being two tourists caught in a summit explosion in 1987) and relatively little destruction. In 1928 it destroyed the village of Mascali on its northeastern flank, though there were no reported casualties, the village being slowly overrun by a lava flow. In 1669 a much larger lava flow destroyed at least 10 villages, reaching the walls of the city of Catania, 40 km to the south, but again without loss of life. In 122 BC a heavy ash fall covered much of the region, causing several buildings to collapse in Catania. The destruction was deemed so severe by the Roman authorities that they granted the city a 10 year tax holiday. In about 6000 BC a landslide on the eastern flank of the volcano is thought to have caused a tsunami that caused destruction around much of the eastern Mediterranean.

Etna is located on the border of the African and European Plates, specifically where Africa is being subducted beneath the European Plate. As it is drawn into the Earth's interior material from the African Plate melts, and the lighter portions rise up through the overlying European Plate, causing a number of volcanoes including Etna and Vesuvius.
 
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Mount Etna, a 3320 m active stratovolcano on eastern Sicily, erupted on Saturday 26 October 2013, producing an ash column which briefly closed airspace over the island and and throwing hot ash and lava out of its crater. This follows a series of small...
 
On the 4th of July 2011 loud explosions were heard from a pit crater on the eastern flank of Mount Etna's southeastern cone (Etna has four cones, the southeast cone in the newest having only formed in 1978). That evening the cone was seen to be glowing, and over...
 
 
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