Report on Etna (Italy) — 4 September-10 September 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 September-10 September 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, 4 September-10 September 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 a series of small and sporadic ash emissions from Etna's New Southeast Crater (NSEC) began during the morning of 3 September, marking the end of four months of complete quiescence. Weak Strombolian activity from NSEC was observed during the early morning of 6 September. At daybreak small ash puffs were emitted once or twice per hour. The same morning intense incandescence emanated from Bocca Nuova. The report stated that since early May only degassing from the summit craters was noted, along with usual bangs and rumblings from deep within the conduit of the Northeast Crater (NEC), which during the past few weeks had become more continuous and louder.
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.