Report on Etna (Italy) — 4 December-10 December 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 December-10 December 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 4 December-10 December 2002. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
According to the Italy's Volcanoes website, as of 5 December explosive activity continued at one of Etna's vents in the northernmost portion of the fissure that opened on Etna's upper S flank on 27 October. Ash emission and lava fountaining were vigorous, with continuous tephra fall affecting areas NE and E of Etna during several days before 5 December. Lava emission seemed to temporarily cease after about 3 weeks of near-continuous activity from vents on the flanks of the new pyroclastic-cone complex. Intermittent seismicity occurred at and around Etna. The largest reported damage occurred at a vacated school building near Giarre that partially collapsed. On 8 December ash emission and lava fountaining at the 2,800-m vent changed to violent Strombolian explosions. The following day ash emission recommenced, and on 10 December explosive activity shifted to the main pyroclastic cone, while the 2,800-m cone became less active, and lava was emitted that fed a flow to the S. By the 11th the lava flow had divided into several branches, with one slowly advancing toward the Rifugio Sapienza tourist area.
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.