Report on Etna (Italy) — 4 April-10 April 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 April-10 April 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 4 April-10 April 2007. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
In the morning of 29 March, an increase in volcanic tremor at Etna was accompanied by lava fountaining and an ash plume that drifted NE. Three fissures opened and produced lava flows. The first two fissures produced lava flows from vents located on the SE flank of Bocca Nuova and in the saddle between Bocca Nuova and Southeast Crater (SEC), in the same location of the October-November 2006 events. The two flows merged down slope and traveled less than 1 km S, halting at the rim of Cratere del Piano. The third fissure opened at the E base of SEC, and the lava flow spread within the upper Valle del Bove. The flows stopped by early afternoon. Ash and lapilli fallout occurred in a narrow zone between SEC, Rifugio Citelli and Giardini Naxos, on the NE 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.