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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

The second observatory dependent from INGV , the Osservatorio Etneo :

Located in Catania , the seat of the Osservatorio Etneo is in charge, as its name suggests, of the most active volcanoes of European states , Etna , but also of Ferdinandea , Pantelleria , and all the volcanoes of the Aeolian islands, especially the always turbulent Stromboli .

Etna. Osservatori e Rifugi. Osservatorio Etneo - Taffara Lu           
Etna Torre del Filosofo - Osservatorio / Rifugio Etneo - phot Taffara Luigi 1929

The Osservatorio was installed on Etna to the Torre del Filosofo until it was destroyed by an eruption in April 1971.
Tazieff, on the Etna at this time, relates this destruction in his typical phrasing :
" ... From the beginning of the eruption in March , its first flow had stumbled against the mighty edifice that was the observatory. Serenely He supported this attack and we continued to live despite eruptive mouths hissed , growled , howled a hundred meters away. Habit help, we hardly were experiencing concern. Except, at times, François Le Guern , still young in this business. (...)
He left and returned immediately, the voice full warning. Time ridging us to catch our backpacks , we rush outside, we go on a high perch block of three meters , and we had the privilege to contemplate the wide lava flow that Fanfan had seen come from upstream, embracing the base of the building, circle and then continue imperturbably its way downstream at the velocity, modest but in retrospect probably scary, of a walking man . (...) Shortly after a new cast came from upstream , identical to the first covered it like a monstrous purple caterpillar. A third , then a fourth , then a fifth ... our familiar refuge disappeared as these flows piled around him. In a few hours the stack reached the roof. The roof was gone , and finally the astronomical dome surmounting .
The flow continued to overlap and the observatory is now buried under ten feet of basalt . As the terminal station of the cable car, an abomination of concrete and scrap which stood a hundred yards downstream. The disappearance of the station comforted my heart, saddened by that of the old observatory.

1971.04.24 Scarpinati giuseppe - INGV
          24/04/1971 - The observatory is surrounded by lava - Photo Giuseppe Scarpinati / INGV

Osservatorio Etneo top nowriteSince then, he is based in Catania , with antennas on Vulcano and Stromboli in the Aeolian Islands , and countless relay stations on the flanks of volcanoes.

The new facilities INGV Catania - Photo INGV
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                      INGV Catania - monitors of the operations room - Photo INGV

The analysis of past eruptions of the two volcanoes in ongoing activity , Etna and Stromboli , are made ​​in everyday items , we briefly resume those that took place in the 19th century  Ferdinandea , Pantelleria and Vulcano .

Ferdinandea, the island with eclipse, is located in the strait between Sicily and the Tunisian coast .

This volcanic area , forming the Campi Flegrei of the Sea of ​​Sicily, included in a depression 1,000 meters deep, is composed of 13 volcanoes, the most famous is Empedocles , who emerged for the last time in 1863 , giving birth to temporary island Ferdinandea located so far to eight meters below sea level

Ferdinandea - Document from the collection of M.Kraff, published by Simkin and Siebert - 1994 - GVP .

This document is not , strictly speaking, a work of art, but remains an important testimony, at a time when there was no photography.
It tells the volcano : July 13, 1831 , when the volcano rises , lava fountains gush along a fissure , in contact with water , lava explodes, spewing  "cypressoïdes clouds " of black ash .

Pantelleria, with the islands of Lampedusa, Linosa and Lampione form Italian Pelagie archipelago, a group of volcanic islands that owes its existence to the presence of a continental rift in the center of Sicily channel .
The bottom of the Sicily Channel back on the shoulders of the rift valley , and emerges to form the flat islands of Lampedusa and Malta. The floor of the rift is a thin crust whose thickness reaches twenty kilometers , while the thickness of the crust is about forty km. in Sicily and Tunisia. The structure of Pantelleria is determined by faults oriented along the direction of the border faults ditches ( NNW / SSE ) .

Laghetto-delle-ondine---G.Roncaglia.jpg                         Pantelleria - The Laghetto delle Ondine - Photo Gino Roncaglia

The island of Pantelleria is the tip of a volcano of 40x30 km and 2150 meters high part. The island covers 83 km² , and is about 13 km long and 8 km wide at maximum .
The volcanic edifice there have emerged 500,000 years , and has continued to grow intermittently until the present time, the last eruption , marine, which took place in 1891.

Pantelleria la côte 2 - G.Roncaglia

 Pantelleria - the stratification of land forming the volcanic island, view from the sea - Photo G.Roncaglia

The morphology of the island is marked by the existence of two nested calderas in the central part:
- The caldera of Vecchia ( 114,000 years)
- And the Monastero caldera , or Cinque Denti (45,000 years), largely filled by the subsequent eruptions products. It contains the shield volcanoes post- caldera Monte Grande and Monte Gibele . Eruptions dated Holocene have constructed pumice cones , lava domes and lava blocks .
Confirming this activity, submarine eruption took place in 1891 at the expense of a vent located off the NW coast of Pantelleria .

Vulcano, north of Sicily in the Aeolian volcanic arc , was established during the last 136,000 years. The island , 3 x 7 km, is mainly characterized by two overlapping calderas : to the SE , the Caldera del Piano ( 100,000 years ) and to the NO, the Caldera della Fossa ( 24,000 to 15,000 years). Vulcanello , and three pyroclastic cones, was connected with Vulcano in 1550.



 Aerial view of the island of Vulcano - in the foreground Vulcanello , then the isthmus between Porto di Levante and Porto di ponante, the La Fossa cone in the center, and on the left, the Piano - Photo B.Duyck , according to a postcard.


                  Vulcano, the La Fossa crater and fumaroles - photo © Bernard Duyck

The last eruption of the Fossa of Vulcano held from 1888 to 1890. The last eruption allowed Giuseppe Mercalli to define the " Vulcanian " type.

Vulcano_-Mercalli1889-14.02.jpg  Vulcano - eruption of 1889 - Photo G.Mercalli / Note the beautiful bombs emitted by the volcano .

Giuseppe Mercalli,  an abbot , a seismologist and volcanologist,  (1850-1914) , taught geology and mineralogy at the University of Catania and volcanology and seismology than to Napoli . In 1911, he became head of the Osservatorio Vesuviano .
He created a scale, subjective, measuring the intensity of earthquakes on the basis of effects , and classified the types of volcanic eruptions.
z-IMG 6216 copie 2                Vulcano - field of fumaroles of La Fossa-II crater rim - Photo © Bernard Duyck



Sources :

- INGV - Catania - Osservatorio Etneo

- INGV - Aprile-giugno 1971: l'eruzione che segnò l'inizio di una nuova fase di attività del vulcano - link   

- Guide des volcans d'Europe et des Canaries - par M. Krafft et de Larouzière - éd. Delachaux & Niestlé

- Ferdinandea sur ce blog - link

- L'île volcanique de Pantelleria - Gilles Brocart & Désiré Corneloup

- Trapani Sicilia - Pantelleria

- Global Volcanism Program - Vulcano

- INGV - Vulcano, isole Eolie



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