Report on Etna (Italy) — 16 February-22 February 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 February-22 February 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 16 February-22 February 2011. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
INGV-CT reported that on 16 February an explosive sequence, presumably from Etna's NE Crater, was detected on 16 February during the late evening. Cloud cover made direct observations difficult. On 18 February the thermal monitoring camera at Montagnola (EMOT) recorded anomalies from the pit crater located on the lower E flank of SE Crater cone. At the same time, the visible-light camera at Montagnola (EMOV) showed intermittent incandescence indicating Strombolian activity, and the seismic network recorded a rapid increase in the volcanic tremor amplitude. This eruptive episode lasted about 11 hours and produced pulsating lava fountains. Lava flows traveled E, following the same path as that of the 12-13 January event, in the direction of the Valle del Bove. Light ashfall occurred on the SW flank of the volcano.
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.