Report on Etna (Italy) — 2 February-8 February 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 February-8 February 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 2 February-8 February 2005. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
INGV-CT reported that the effusive eruption that began at Etna on 7 September 2004 continued through 27 January 2005. On 18 January the INGV-CT web camera recorded a dense, pulsating gas plume emanating from the summit of Northeast Crater for a few minutes. During the afternoon of the 18th, a new lava flow formed upslope along the 2,620-m eruptive fissure at about 2,450 m elevation. The lava flow spread about 200 m SE along the middle wall of the western Valle del Bove. The flow moved slowly, stopping after about 24 hours. Lava emission stopped from the ephemeral vents below 2,000 m elevation. The lower ephemeral vents started to emit lava again on 19 January. During the afternoon of 22 January, two new lava flows traveled from 2,400 m elevation, along the same lava-tube system fed by the 2,620-m-elevation vent. Two parallel, fast-moving flows spread E. They were still visible on images recorded on 27 January by the INGV-CT web camera at Milo. In addition, a number of ephemeral vents and small flows at the lower end of the lava tube were visible.
Geologic Background. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.