Some scenes observed during the July-August 2001 eruption of Etna bear a certain irony to them, like the one shown in the two photographs above. On 31 July, lava flows emitted from a group of vents at 2570 m elevation have arrived very close to the buildings of the tourist station at the Rifugio Sapienza. Most of the lava is successfully contained by earth barriers, but small overflows over the crest of one barrier seriously threaten a building of the local tourism authority (seen in the photograph at right). Fireman are spraying water onto the lava in order to prevent it from reaching the building. A few meters away, a group of spectators (left photograph), apparently not all that excited to judge from their expressions, are watching the scene, while a huge poster behind their backs announcing "Specialty: the lava of Etna". But what is generally much appreciated by the tourists has now become a serious menace

Etna photo gallery: 2001
Etna makes the news

On 25 July 2001, the eruption enters into its most intense and most spectacular phase, which is to last about five days. Eruptive activity is occurring at no less than seven different eruptive fissures, and it is gradually becoming evident that two of them (on the southern flank at 2100 and 2570 m elevation) belong to a different system of feeder conduits than the other fissures. The lavas emitted from the two southernmost sites contain abundant inclusions of sedimentary rock (entrained by the magma when it rose through the sedimentary basement of the volcano) and, more exceptionally, a mineral named amphibole (which contains limited amounts of H2O in its crystal structure).
Following about one week of ash-rich phreatomagmatic activity, the vents at 2570 m elevation change their activity during the night of 24-25 July, and instead of relatively silent ash emissions there are now magmatic explosions, accompanied by tremendous detonations, and lava begins to flow out, producing the most devastating flows of the entire eruption. During the following days, a huge new cone begins to grow around the main vent at 2570 m, and the morphology of the upper south flank of Etna changes beyond recognition. Its lava flows burn and destroy the arrival station of the cable car, and everything man-made around the growing cone is utterly devastated.
During the last days of July, while the newly forming cone experiences the climax of its activity, the highest of the eruptive fissures, on the northeastern and southeastern sides of the Southeast Crater, cease their activity, and it soon becomes evident that the 2001 flank eruption is gradually losing strength. During the first week of August, more eruptive fissures progressively shut down, until, on the late evening of 9 August, also the vents at 2100 m elevation fall silent and the eruption is over after 24 days.

Yet another surprise during the 2001 eruption: a profound change in the style of eruptive activity at the vents at 2570 m elevation during the night of 24-25 July, which is most evident from the disappearance of the imposing ash column (still visible in the photograph at left, taken on 24 July, but virtually absent in the right photograph taken 24 hours later from nearly the same spot). Ash emission has been replaced by nearly continuous magmatic explosions that produce very loud detonations, audible even in Catania, some 25 km away, at rush hour

Two photographs of the erupting volcano from the east, 25 July 2001. Gas emission marks the summit craters at right (left photo), while a vertical gas plume charged with little ash is rising from the vents at 2570 m. Right photograph is a zoom on that site, showing a dark plume generated by explosive activity, and a white plume issuing from newly formed effusive vents

View towards the Southeast Crater from east on 25 July 2001, with gas escaping from the summit of its cone (the peculiar dark rock feature on its eastern side is the "Levantino" vent, which had been active for half a year before the July-August 2001 eruption, and continued to emit lava into this eruption). A brownish plume rises from the Bocca Nuova at right, and a small, light-colored plume at left marks the site of the eruptive fissure at 2950 m elevation, the first of the new eruptive fissures to open on 17 July

Places seen during the days before, but no longer under the shadow of the ash column: the Rifugio Sapienza area is seen in the left photograph, with mild activity at the eruptive fissure at 2100 m visible at extreme right, and light-colored plumes rising from the vents behind the Montagnola. When zooming on the crest of the Montagnola, the explosions from the vents hidden behind it are seen to eject abundant huge, glowing bombs (center photograph). It seems as though the change in the dynamics of these vents has deprived the fissure at 2100 m, in the right photograph, of its energy. On 25 July, when these photographs were taken, there was only very minor Strombolian activity at the main cone at the 2100 m fissure, and lava outflow from this fissure had diminished in rate

Etna's new violent baby: following the shift from phreatomagmatic to magmatic activity at the vents at 2570 m elevation, a large cone begins to grow around the most vigorous of these vents, seen here from about 2950 m on 26 July 2001. At that time, the cone is highly irregular, its eastern rim being highest (about 50-60 m). The building in the foreground is the Torre del Filosofo mountain hut, which has already survived several assaults by lava flows from the Southeast Crater and is going to be left unharmed also by this eruption (another eruption, in late 2002, will bury the building under a thick pyroclastic deposit). Behind the actively growing new cone lies the Montagnola, a large pyroclastic cone formed during an eruption in 1763 which was similarly explosive

Peculiar constructive features, known as "hornitos" (a Spanish word that means "little ovens"), are growing at the eruptive vents at 2950 m altitude, which were the first to open during the eruption, on the early morning of 17 July 2001. I first got to see these vents nine days later, on 26 July, when their activity was still vigorous and occurred in at least six places. The photograph at left shows the largest of the new hornitos, about 10 m tall, seen from west, about 80 m away. The other two views were taken from the small "Sudestino" cone, which had formed in the spring of 2000, and permitted to watch the activity of the hornitos from above. The lower vents in the foreground sometimes bulged alarmingly before they exploded (one such explosion is seen in the photograph at right), although the observation post was fairly safe. Activity at the largest, steeply sided hornito, was more intermittent and less spectacular. In the distance lies yet another small cone, about 20 m high, which formed at about 2700 m elevation when the second eruptive fissure opened on the afternoon of 17 July

More images of the hornitos at 2950 m in activity on 26 July 2001. The left and center photographs also show the large growing cone at 2570 m in the right background. A violent explosion at one of the smaller vents in the row of hornitos is seen in the photograph at right

Seen from the summit of the "Sudestino", one of the vents at 2950 m elevation produces a large magma blister that eventually explodes. In the background the roof of the Torre del Filosofo mountain hut can be seen before the growing cone at 2570 m elevation

Continue to 28 July 2001

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Copyright © Boris Behncke, "Italy's Volcanoes: The Cradle of Volcanology"