Report on Etna (Italy) — 22 December-28 December 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 December-28 December 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 December-28 December 2010. 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 a strong explosion from the W vent of Etna's Bocca Nuova crater at 0446 on 22 December produced an ash plume that rose a few hundred meters above the summit and drifted NE. The explosion of hot, though not incandescent, material and subsequent ash emission was observed and recorded by thermal cameras at Montagnola and Nicolosi (14 km S). Light ashfall was reported as far away as Linguaglossa (18 km NE). Small emissions of reddish-brown ash continued to occur before noon.
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.