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Activity of the Sicilian volcanoes during November 2011

2010-2011_pit_to_New_SEC_730

Comparison photographs taken from the same position but one year apart show the growth of the New Southeast Crater cone, the result of the accumulation of pyroclastic material during the 18 paroxysmal eruptive episodes between January and November 2011. The viewpoint in both images is close to the multiparameter monitoring station of "Belvedere", located about 0.9 km southeast of the crater. The upper photograph, taken on 9 November 2010, shows a dense column of white vapor rising from the pit crater that would later become the New Southeast Crater seen in the image below. The height of the new cone above its eastern base (at right) is about 200 m. Photos taken by Boris Behncke, INGV-Osservatorio Etneo (Catania)

ETNA

During the month of November 2011, one single paroxysmal eruptive episode has occurred at the New Southeast Crater (New SEC), on the 15th, following a quiescent interval of 23 days. This episode led to further growth of the New SEC cone, whose summit now stands approximately 180-200 m above its base. During the entire month, the usual deep-seated explosions continued within the conduit of the Northeast Crater, accompanied by strong degassing and deep rumbling sounds audible when standing on the crater rim.

All times are in GMT (= local time -1).

15 November 2011 paroxysmal eruptive episode

The 18th paroxysmal eruptive episode of the year 2011 was preceded by only few hours of increasing activity, starting around 06:30 with the emission of a small lava flow from the eruptive fissure on the southeast flank of the New SEC cone. Weak Strombolian activity from the interior of the crater and from the southeast flank fissure began between 08:00 e 09:00, and then progressively increased, until, around 11.15, it passed into lava fountaining and the formation of an eruption column. As during previous paroxysmal episodes, also this one came from various emission points, with some aligned along the fracture that cuts the southeast flank of the New SEC cone. The eruption column led to the fall of abundant, coarse-grained pyroclastic material in the summit area, whereas the finer pyroclastic fraction, ash and lapilli, fell on the southeast flank of Etna, affecting numerous population centers including Acireale.

During the paroxysm, which ended toward 12.50, the lava flow descended the western slope of the Valle del Bove and divided into numerous branches that came to a halt at the base of the steep slope, to the west and uphill of Monte Centenari.

 

STROMBOLI

Stromboli volcano is in a state of persistent eruptive activity, normally with explosions of medium to low intensity occurring from a number of vents located within the summit crater. During November 2011, the activity continued at fluctuating levels, and with frequent episodes of spattering. The activity was concentrated at the two active vent areas, in the northern and southern sectors of the crater terrace; the spattering episodes occurred in the southern area and did not lead to the formation of any lava flows.