Report on Etna (Italy) — 29 January-4 February 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 January-4 February 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 January-4 February 2014. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
INGV reported that on 28 January there was a gradual but steady decrease of activity at Etna's New Southeast Crater (NSEC). Weak and sporadic Strombolian explosions were detected at night, but then the thermal cameras recorded no anomalies associated with Strombolian activity. Lava flows from two vents at the base of the NSEC cone continued to effuse at a very low rate. Weather conditions almost entirely prevented observations of Etna from the morning of 30 January until the evening of 3 February. Late on 3 February observers noted that the lava flow remained active and was several hundred meters long. Almost continuous ash emissions from NSEC began at about 1300 on 4 February and continued into the night; about 5-10 ash puffs were separated by steam emissions. Ash plumes drifted E. After sunset jets of hot material were observed rising 100 m above the crater rim. At 2000 the ash emissions and injection of incandescent material ceased, but the lava flow continued and reached 1 km long.
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.