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Earth of fire

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

The Phlegraean Fields of the Sicily Sea consists of a group of submarine volcanoes that are built in a depression located at 1000 m. depth in the Strait of Sicily, between his SW coast and the tip NE of Tunisia. They formed banks covered with cones , some of which grow up to close to the sea level.

Schema bati-morfologico del Canale di Sicilia. FL fossa di
Schéma bathy-morphological of the strait of Sicily  - General Bathymetric Chart da modificato of the Oceans 2003 - doc . INGV
Southwest of the Phlegrean fields , the island of Pantelleria - to the south , the island of Linosa . (FL : Fossa di Linosa )

The Banco Graham, still largely unknown and unmonitored, point to only 6.9 meters below the sea level. The first exploration dated from 1890 by the Italian Hydrographic Institute . In 1925 , teams from the research vessel "Admiral Magnaghi I " confirms the existence of the bank, 37 ° 09 ' N - 12 ° 43' E, with a summit of 30m ² at a depth of between 8 and 12 meters. New explorations by the Hydrographic Institute in 1989 and 2002 show no changes in bathymetry.

ferdinandea - Ferdinandea, at approximately its largest. Pu
Ferdinandea island  at its greatest extent in 1831 - doc . taken from the Journal of the Ship Il Gustavo


Ferdinandea 1831 C.Gemellaro INGV The eruption of Ferdinandea in 1831 , of Surtseyan type with cypressoïds clouds  -doc. C.Gemellaro / INGV

Submarine eruptions were reported at various times in ancient literature during the first Punic War ( War between Rome and Carthage between 264 and 241 BC) , and between 17 ° and 20 ° centuries. Three times, an ephemeral island formed during eruptions in 1701 , 1831 and 1863.

After its emergence in 1831 , the eclipse island reaches a considerable size (5 km . circumference and 65 m. height) , and is claimed in turn by the English, French , Spanish and Italians ... of where its many names : Graham, Ferdinandea , Julia, Sciacca, or Proserpine island. The United Nations Convention on the Law of the Sea (Montego Bay 1982) finally assigns the rights of the area to Italy on geographical territorial basis.

Ferdinandea plaque - Summitpost
The remains of the original plate, where it is written " " Questo lembo di terra una volta isola Ferdinandea era e sara sempre del popolo siciliano ... Ferdinando di Borbone, Delle due Sicilii, Duca di Castro ..."." -  It was replaced by a new one in 2002. - Doc . Summitpost .
 
Ferdinandea rilievo 730Image 3D bathymetric of Empedocles , with Banco Graham ( or Ferdinandea ) to the west, to the east, the Banco Terribile and the Banco Nerita to the northeast . - Doc . INGV

In 2006, the INGV indicates that Ferdinandea island could be part of a huge underwater volcano, 30 km to 25 , up to iron horse , named Empedocles , named after the philosopher born in Agrigento and death on Etna ... Ferdinandea is the name given to the summit of the volcano Empedocles . On this occasion , Enzo Boschi , president of the INGV , said "the existence of such a volcanic group is not cause for concern ."
Empedocles, of area comparable to that of Etna but with a more modest height, poses no immediate danger, its activity is limited to the emission of volcanic gases .
 ferdinandea (1) 672-458 resize
          Launching of the ROV of INGV on the Phlegrean fields of the Sicily sea - doc . INGV

The volcanic system includes a dozen buildings in a radius of 5 km., of varying sizes, with diameters between 50 and 1,500 m. These buildings are aligned NW-SE in the Sicily Channel .  

The cone responsible for the eruption of 1831 is part of a device consisting of two coalescing cones on a common basis, elongated NW- SE, and their apex are 600 m apart . The building NW of Ferdinandea it has a frustoconical shape and a large crater, which fed lava flows that have invaded the floor at a depth of over 200 m. In the center, we see the remains of another crater rim . Its north-east side houses an active
field of fumaroles
 
Ferdinandea mappa dettaglio 730 - INGV
A : Map of Banco Graham, with coalescing buildings - B: Ferdinandea to the right - the other cone : in 1: the edge of the crater - 2 : lava flows - 3 : edge a second crater - 4 : signs of intra- cratéric activity - in 5 :
field of fumaroles -  6 : another building in horseshoe, having within it a small regular cone. - Doc . INGV

To the east of Ferdinandea group, the Banco Terribile rises to 20 m. subsurface and northeast , the Banco Nerita is only 16.5 m. below the sea level .
During the exploration campaign , precise sonar survey has identified nine distinct craters. In addition to samples of rocks and gases, three seismic stations were installed on the seabed.

Pinne is a cone , located in
 the Phlegrean fields of the Sicily sea, and known for four historic eruptions during the First Punic War, circa 253 BC. , in October 1846 ( VEI 2), in 1867 and the last in September 1911, but uncertain.

 

 

Sources :

- Global Volcanism Program - Campi Flegrei Mar Sicilia

- INGV Catania - Isola Ferdinandea - link

- Isola Ferdinandea ... il blog - link

- Sur ce blog, Ferdinandea - Pantelleria - Pantelleria et Linosa

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