Report on Etna (Italy) — 4 July-10 July 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 July-10 July 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 4 July-10 July 2001. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3320 m
All times are local (unless otherwise noted)
After 4.5 days of low-level activity at Etna, an eruption occurred at Southeast Crater on 4 July that lasted for approximately 5 hours. The episode began with lava flowing from the NNE vent towards the NE and SSE and was followed by modest Strombolian activity. At the summit vent powerful explosions sent an incandescent fountain up to 400-500 m high and several large magma bubbles burst sending fragments to the base of the Southeast Crater cone. A dense tephra column rose from the summit vent and deposited ash on Etna's SE flank. Fine ash and 3- to 5-mm-long Pele's hair fell as far as the town of Acireale, ~20 km SE of the volcano. On 7 July another eruptive episode lasted for approximately 1 hour at Southeast Crater. The episode consisted of lava flows and the eruption of black ash and small volcanic blocks that reached a height of ~1 km above the volcano and drifted to the E.
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.