Report on Etna (Italy) — 9 January-15 January 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 January-15 January 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 January-15 January 2013. 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 during 22 November-early December 2012 weak glow emanated from Etna's New Southeast Crater (NSEC) caused by the emission of high-temperature gas. The glow was most intense during 1-2 December, then rapidly diminished and reappeared on 24 December. During 25-27 December sporadic and weak ash emissions from NSEC were accompanied by increased gas emissions. On the evening of 3 January a strong glow was briefly observed.
Vigorous Strombolian activity at Bocca Nuova Crater began at night during 9-10 January, three months after the last episode. At 0000 on 10 January a rapid rise in tremor amplitude was detected. Ten minutes later a video camera recorded the first incandescent burst in the E part of the crater, which progressively became stronger and more frequent. At 0350 jets of incandescent fragments rose significantly higher than the crater rim. In daylight the phenomenon was no longer visible via the surveillance cameras; the volcanic tremor amplitude remained elevated but started to decrease around 1200. In the early morning of 15 January volcanic tremor amplitude rapidly decreased, marking the cessation of Strombolian activity in the Bocca Nuova Crater.
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.