Report on Etna (Italy) — 5 February-11 February 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 February-11 February 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 5 February-11 February 2003. 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 Etna flank eruption that began on 27 October 2002 ended on 28 January 2003 after 3 months of activity. In January, lava flows and Strombolian explosions were confined to Etna's S flank at a 2,750-m-elevation vent. Lava flows emitted from this vent formed a fan, covering the previous lava-flow field. Strombolian activity from the 2,750-m-cinder cone significantly declined on 27 January and ended on 29 January. In addition, lava flows slowed down on the 27th and by the 29th were no longer fed and were cooling down. At the same time there was a significant decrease in SO2 emission to a minimum of 2,000 tons/day on 29 January. Volcanic-tremor amplitude also showed a marked decrease on 27 January. The end of the eruption was interpreted to occur on 28 January at 2240 when volcanic tremor decreased to background levels.
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.