Report on Etna (Italy) — 10 October-16 October 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 October-16 October 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, 10 October-16 October 2012. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3320 m
All times are local (unless otherwise noted)
Sezione di Catania - Osservatorio Etneo reported that on the evening of 2 October weak Strombolian activity resumed within Etna's Bocca Nuova crater, from the same vent on the SE part of the crater floor that was active in July and August 2012. On 3 October the activity was accompanied by a small inter-crater lava flow on the S part of the floor. Over the next few days the activity slowly intensified and a small new cone developed over the old cone formed during July-August, which had subsequently nearly completely collapsed. Volcanic tremor amplitude rapidly increased on the evening of 6 October at the same time eruptive activity intensified. Lava flowed towards the W part of the crater floor and lava fountains pulsated. The intensity of both the eruptive activity and the volcanic tremor amplitude peaked just after midnight on 7 October, and strong glow from the crater was observed from nearby populated areas. Some of the lava jets rose well above the crater rim. Activity decreased at 0430, and the next day dropped to the lowest levels recorded for many weeks.
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.