Report on Etna (Italy) — 14 May-20 May 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 May-20 May 2008
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 May-20 May 2008. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3320 m
All times are local (unless otherwise noted)
INGV-CT reported continuous ash emission and periodic Strombolian activity from multiple vents, possibly along an E-trending fissure E of Etna's summit craters, during 10-19 May. Observations were limited due to cloud cover. Ash plumes rose to approximate attitudes of 3.5-7.3 km (11,500-24,000 ft) a.s.l. and sulfur dioxide emissions were elevated. Lava flows that issued from the fissure and another fissure to the N traveled about 6 km E into the Valle del Bove during 13-15 May. Ash-and-gas explosions were occasionally accompanied by roaring noises on 14 May. Explosions and roaring noises were audible on 20 May. [Correction: Ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l.]
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.