Mount Etna


Mount Etna, or Etna, is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina and Catania. It lies above the convergent plate margin between the African Plate and the Eurasian Plate. It is the highest active volcano in Europe outside the Caucasus and the highest peak in Italy south of the Alps with a current height of, though this varies with summit eruptions. Etna covers an area of with a basal circumference of. This makes it by far the largest of the three active volcanoes in Italy, being about two and a half times the height of the next largest, Mount Vesuvius. Only Mount Teide on Tenerife in the Canary Islands surpasses it in the whole of the European–North-African region west of the Black Sea. In Greek mythology, the deadly monster Typhon was trapped under this mountain by Zeus, the god of the sky and thunder and king of gods, and the forges of Hephaestus were said also to be underneath it.
Mount Etna is one of the world's most active volcanoes and is in an almost constant state of activity. The fertile volcanic soils support extensive agriculture, with vineyards and orchards spread across the lower slopes of the mountain and the broad Plain of Catania to the south. Due to its history of recent activity and nearby population, Mount Etna has been designated a Decade Volcano by the United Nations. In June 2013, it was added to the list of UNESCO World Heritage Sites.
, Peloritani mountains

Etymology and folklore

The word Etna is from the Greek αἴθω, meaning "I burn", through an iotacist pronunciation. In Classical Greek, it is called Αἴτνη, a name given also to Catania and the city originally known as Inessa. In Latin it is called Aetna. In Arabic, it was called جبل النار Jabal al-Nār.
It is also known as Mungibeddu in Sicilian and Mongibello or Montebello in Italian. According to another hypothesis, the term Mongibello comes from the Latin Mulciber, one of the Latin names of the Roman god Vulcan. Another theory is that Mongibello came from the Italian word monte plus the Arabic word jabal, both meaning "mountain."
Today, the name Mongibello is used for the area of Mount Etna containing the two central craters, and the craters located southeast and northeast of the volcanic cone.
The name Mongibel is found in Arthurian Romance, as the name of the otherworld castle of Morgan le Fay and her half-brother, King Arthur, localised at Etna, according to traditions concerning them derived from the stories told by the Breton conteurs who accompanied the Norman occupiers of Sicily.
What were originally Welsh conceptions concerning a dwarf king of a paradisal, Celtic underworld became attached to the quasi-historic figure of Arthur as "Ruler of the Antipodes" and were then transplanted into a Sicilian milieu, by Bretons impressed by the already otherworldly associations of the great, volcanic mountain of their new home. Mediaevalist Roger Sherman Loomis quotes passages from the works of Gervase of Tilbury and Caesarius of Heisterbach featuring accounts of Arthur's returning of a lost horse which had strayed into his subterranean kingdom beneath Etna. Caesarius quotes as his authority for the story a certain canon Godescalcus of Bonn, who considered it a matter of historical fact of the time of Emperor Henry's conquest of Sicily circa 1194. Caesarius employs in his account the Latin phrase in monte Gyber to describe the location of Arthur's kingdom.
The Fada de Gibel of the Castle of Gibaldar appears in Jaufre, the only surviving Arthurian romance in the Occitan language, the composition of which is dated to between 1180 and 1230. However, in Jaufre, while it is clear from her name that the fairy queen in question is Morgan le Fay, the rich underworld queendom of which she is the mistress is accessed, not through a fiery grotto on the slopes of Etna, but through a 'fountain' – a circumstance more in keeping with Morgan's original watery, rather than fiery, associations, before her incorporation into the folklore of Sicily. For another Sicilian conception of the fairy realm or castle of Morgan le Fay – see Fata Morgana re. an optical phenomenon common in the Strait of Messina.

History of volcanic eruptions

Geological history

Volcanic activity first took place at Etna about 500,000 years ago, with eruptions occurring beneath the sea off the ancient coastline of Sicily. About 300,000 years ago, volcanism began occurring to the southwest of the summit, then activity moved towards the present centre 170,000 years ago. Eruptions at this time built up the first major volcanic edifice, forming a stratovolcano in alternating explosive and effusive eruptions. The growth of the mountain was occasionally interrupted by major eruptions, leading to the collapse of the summit to form calderas.
From about 35,000 to 15,000 years ago, Etna experienced some highly explosive eruptions, generating large pyroclastic flows, which left extensive ignimbrite deposits. Ash from these eruptions has been found as far away as south of Rome's border, to the north.
Thousands of years ago, the eastern flank of the mountain experienced a catastrophic collapse, generating an enormous landslide in an event similar to that seen in the 1980 eruption of Mount St. Helens. The landslide left a large depression in the side of the volcano, known as 'Valle del Bove'. Research published in 2006 suggested this occurred around 8,000 years ago, and caused a huge tsunami, which left its mark in several places in the eastern Mediterranean. It may have been the reason the settlement of Atlit Yam, now below sea level, was suddenly abandoned around that time.
The steep walls of the valley have suffered subsequent collapses on numerous occasions. The strata exposed in the valley walls provide an important and easily accessible record of Etna's eruptive history.
The most recent collapse event at the summit of Etna is thought to have occurred about 2,000 years ago, forming what is known as the Piano Caldera. This caldera has been almost entirely filled by subsequent lava eruptions but is still visible as a distinct break in the slope of the mountain near the base of the present-day summit cone.
Mount Etna is moving towards the Mediterranean Sea at an average rate of per year, the massif sliding on an unconsolidated layer above the older sloping terrain.

Eruptions

Historical eruptions

Eruptions of Etna follow a variety of patterns. Most occur at the summit, where there are five distinct craters – the Northeast Crater, the Voragine, the Bocca Nuova, and the Southeast Crater Complex. Other eruptions occur on the flanks, which have more than 300 vents ranging in size from small holes in the ground to large craters hundreds of metres across. Summit eruptions can be highly explosive and spectacular but rarely threaten the inhabited areas around the volcano. In contrast, flank eruptions can occur down to a few hundred metres altitude, close to or even well within the inhabited areas. Numerous villages and small towns lie around or on cones of past flank eruptions. Since the year AD 1600, at least 60 flank eruptions and countless summit eruptions have occurred; nearly half of these have happened since the start of the 20th century. Since 2000, Etna has had four flank eruptions – in 2001, 2002–2003, 2004–2005, and 2008–2009. Summit eruptions occurred in 2006, 2007–2008, January–April 2012, in July–October 2012 and again in December 2018.
The first known record of eruption at Etna is that of Diodorus Siculus.
In 396 BC, an eruption of Etna reportedly thwarted the Carthaginians in their attempt to advance on Syracuse during the Second Sicilian War.
A particularly violent explosive summit eruption occurred in 122 BC, and caused heavy tephra falls to the southeast, including the town of Catania, where many roofs collapsed. To help with reconstruction after the devastating effects of the eruption, the Roman government exempted the population of Catania from paying taxes for ten years.
The Roman poet Virgil gave what was probably a first-hand description of an eruption in the Aeneid.
During the first 1500 years AD, many eruptions went unrecorded ; among the more significant are: an eruption in about 1030 AD near Monte Ilice on the lower southeast flank, which produced a lava flow that travelled about 10 km, reaching the sea north of Acireale; the villages of Santa Tecla and Stazzo are built on the broad delta built by this lava flow into the sea; an eruption in about 1160, from a fissure at only elevation on the south-southeast flank near the village of Mascalucia, whose lava flow reached the sea just to the north of Catania, in the area now occupied by the portion of the city named Ognina.
Rabban Bar Sauma, a Chinese traveller to the West, recorded the eruption of Etna on 18 June 1287.
The 1669 eruption, Etna's most destructive since 122 BC, started on 11 March 1669 and produced lava flows that destroyed at least 10 villages on its southern flank before reaching the city walls of the town of Catania five weeks later, on 15 April. The lava was largely diverted by these walls into the sea to the south of the city, filling the harbour of Catania. A small portion of lava eventually broke through a fragile section of the city walls on the western side of Catania and destroyed a few buildings before stopping in the rear of the Benedictine monastery, without reaching the centre of the town. Contrary to widespread reports of up to 15,000 human fatalities caused by the lava, contemporaneous accounts written both in Italian and English mention no deaths related to the 1669 eruption. Therefore, it is uncertain where the enormous number of fatalities can be attributed. One possibility is confusion between this eruption and an earthquake that devastated southeast Sicily 24 years later in 1693. A study on the damage and fatalities caused by eruptions of Etna in historical times reveals that only 77 human deaths are attributable with certainty to eruptions of Etna, most recently in 1987 when two tourists were killed by a sudden explosion near the summit.

Recent eruptions

A large lava flow from an eruption in 1928 led to the destruction of a population centre for the first time since the 1669 eruption. The eruption started high on Etna's northeast flank on 2 November. Then new eruptive fissures opened at decreasing elevations down the flank of the volcano. The third and most vigorous of these fissures opened late on 4 November at an unusually low elevation, approximately above sea-level, in a zone known as Ripe della Naca. The village of Mascali, lying down-slope of the Ripe della Naca, was almost completely destroyed in two days. Only a church and a few surrounding buildings survived in the north part of the village, called Sant'Antonino or "il quartiere". During the last days of the eruption, the flow interrupted the Messina-Catania railway line and destroyed the train station of Mascali. The event was used by Benito Mussolini's fascist regime for propaganda purposes, with the evacuation, aid, and rebuilding operations being presented as models of fascist planning. Mascali was rebuilt on a new site, and its church contains the Italian fascist symbol of the torch, placed above the statue of Jesus Christ.
Other major 20th-century eruptions occurred in 1949, 1971, 1979, 1981, 1983 and 1991–1993. In 1971, lava buried the Etna Observatory, destroyed the first generation of the Etna cable-car, and seriously threatened several small villages on Etna's east flank. In March 1981, the town of Randazzo on the northwestern flank of Etna narrowly escaped destruction by unusually fast-moving lava flows. That eruption was remarkably similar to one in 1928 that destroyed Mascali. The 1991–1993 eruption saw the town of Zafferana threatened by a lava flow, but successful diversion efforts saved the town with the loss of only one building a few hundred metres from the town's margin. Initially, such efforts consisted of the construction of earth barriers built perpendicularly to the flow direction; it was hoped that the eruption would stop before the artificial basins created behind the barriers would be completely filled. Instead, the eruption continued, and lava surmounted the barriers, heading directly toward Zafferana. Engineers then decided to use explosives near the source of the lava flow, to disrupt a very efficient lava tube system through which the lava travelled for up to without losing significant heat or fluidity. The main explosion on 23 May 1992 destroyed the tube and forced the lava into a new artificial channel, far from Zafferana, and it would have taken months to re-establish a long lava tube. Shortly after the blasting, the rate of lava emission dropped, and during the remainder of the eruption the lava never advanced close to the town again.
Following six years of unusually intense activity at the four summit craters of Etna, the volcano produced its first flank eruption since 1991–1993 in July–August 2001. This eruption, which involved activity from seven distinct eruptive fissures mostly on the south slope of the volcano, was a mass-media eruption because it occurred at the height of the tourist season and numerous reporters and journalists were already in Italy to cover the G8 summit in Genoa. It also occurred close to one of the tourist areas on the volcano, and thus was easily accessible. Part of the "Etna Sud" tourist area, including the arrival station of the Etna cable car, were damaged by this eruption, which otherwise was a rather modest-sized event by Etna standards.
In 2002–2003, a much larger eruption threw up a huge column of ash that could easily be seen from space and fell as far away as Libya, south across the Mediterranean Sea. Seismic activity in this eruption caused the eastern flanks of the volcano to slip by up to two metres, and many houses on the flanks of the volcano experienced structural damage. The eruption also completely destroyed the tourist station Piano Provenzana, on the northeastern flank of the volcano, and part of the tourist station "Etna Sud" around the Rifugio Sapienza on the south flank. Footage from the eruptions was recorded by Lucasfilm and integrated into the landscape of the planet Mustafar in the 2005 film . The Rifugio Sapienza is near the site of a cable car station which had previously been destroyed in the 1983 eruption; it has now been rebuilt. Following a slow and non-destructive lava outflow on the upper southeastern flank between September 2004 and March 2005, intense eruptions occurred at the Southeast Crater in July–December 2006. These were followed by four episodes of lava fountaining, again at the Southeast Crater, on 29 March 11 April 29 April and 7 May 2007. Ash emissions and Strombolian explosions started from a vent on the eastern side of the Southeast Crater in mid-August 2007.
On 4 September 2007, a major episode of lava fountaining occurred from the new vent on the east side of the Southeast Crater, also producing a plume of ash and scoriae which fell over the east flank of the volcano. A lava flow travelled about into the uninhabited Valle del Bove. This eruption was visible far into the plains of Sicily, ending the following morning between the hours of 5 to 7 a.m. local time. Catania-Fontanarossa Airport shut down operations during the night for safety precautions.
An eruption on the morning of 13 May 2008, immediately to the east of Etna's summit craters was accompanied by a swarm of more than 200 earthquakes and significant ground deformation in the summit area. The eruption continued at a slowly diminishing rate for 417 days, until 6 July 2009, making this the longest flank eruption of Etna since the 1991–1993 eruption that lasted 473 days. Previous eruptions, in 2001, 2002–2003, and 2004–2005 had lasted 3 weeks, 3 months, and 6 months, respectively. Lava flows advanced 6.5 km during the first few days of this eruption but thereafter stagnated at many minor distances from the vents; during the last months of the eruption lava rarely advanced more than 1 km downslope.
Through January 2011 to February 2012, the summit craters of Etna were the site of intense activity. Frequent eruptions and ash columns forced the authorities to shut down the Catania airport on several occasions.
The July 2011 episode also endangered the Sapienza Refuge, the main tourist hub on the volcano, but the lava flow was successfully diverted. In 2014, a flank eruption started involving lava flows and strombolian eruptions. This was the first flank eruption since 2008–09
On 3 December 2015, an eruption occurred which climaxed between 03:20 and 04:10 local time. The Voragine crater exhibited a lava fountain which reached in height, with an ash plume which reached in height. The activity continued on the following days, with an ash plume that reached in height that forced Catania airport to shut down for a few hours. Volcanic gas emissions from this volcano are measured by a Multi-Component Gas Analyzer System, which detects pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.
An eruption on 16 March 2017 injured 10 people, including a BBC News television crew, after magma exploded upon contact with snow.
An eruption on 24 December 2018, following a dyke intrusion at shallow depth, spewed ash into the air, forcing the closure of airspace around Mount Etna. Two days later, a magnitude 4.9 earthquake shook the nearby city of Catania, damaging buildings and injuring four people.

Volcanic explosivity index of recent eruptions

The Global Volcanism Program has assigned a volcanic explosivity index to all of Mount Etna's eruptions since January 1955:

Smoke rings

In the 1970s Etna erupted smoke rings, one of the first captured events of this type, which are extremely rare. This happened again in 2000. Video footage of 8 June 2000 event was captured by naturalist filmmaker Geoff Mackley. Another event occurred on 11 April 2013.

Geopolitical boundaries

The borders of ten municipalities meet on the summit of Mount Etna, making this point one of elevenfold complexity.

Facilities

Etna is one of Sicily's main tourist attractions, with thousands of visitors every year. The most common route is through the road leading to Sapienza Refuge ski area, lying at the south of the crater at elevation of 1910 m. From the Refuge, a cableway runs uphill to an elevation of 2500 m, from where the crater area at 2920 m is accessible.
Ferrovia Circumetnea – Round-Etna railway – is a narrow-gauge railway constructed between 1889 and 1895. It runs around the volcano in a 110-km long semi-circle starting in Catania and ending in Riposto 28 km north of Catania.
There are two ski resorts on Etna: one at the Sapienza Refuge, with a chairlift and three ski lifts, and a smaller one on the north, at Piano Provenzana near Linguaglossa, with three lifts and a chairlift.
Sapienza Refuge was the finish of Stage 9 of the 2011 Giro d'Italia and Stage 4 of the 2017 Giro.