Report on Etna (Italy) — 28 March-3 April 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 March-3 April 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 March-3 April 2012. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
Sezione di Catania - Osservatorio Etneo reported that the twenty-third paroxysmal eruptive episode since January 2011 took place at New SE Crater (New SEC) of Etna during the morning of 1 April following two weeks of quiescence. The episode was characterized by tall lava fountains from vents within the crater and on the SE flank of its cone, a gas-and-tephra plume, and lava flows descending toward the Valle del Bove. The paroxysmal phase lasted about 1.5 hours and ended just before daybreak. Ash and lapilli fell over the SE sector of the volcano, affecting mainly the area between Monterosso and Zafferana Etnea, but also the area between Acireale and Giarre, further downslope.
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.