Report on Etna (Italy) — 30 July-5 August 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 July-5 August 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 30 July-5 August 2003. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3320 m
All times are local (unless otherwise noted)
During the end of July, heightened seismicity occurred in the eastern area of Etna. Also, vigorous degassing continued at Northeast crater, and less intense degassing occurred at Bocca Nuova crater. Four small earthquakes with magnitudes up to 2.6 occurred on 30 July between the villages of Milo and Zafferana on the volcano's E flank.
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.