Report on Etna (Italy) — 10 January-16 January 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 January-16 January 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Etna (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 10 January-16 January 2001. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
There has been no new eruptive activity at the summit craters of Etna since early December. Beginning on 7 January 2001, degassing from Bocca Nuova became more rhythmic, indicating some deep explosive activity. On 11 January gas emissions from the Bocca Nuova became more intense and came in distinct puffs. Southeast Crater continued to emit heat; an incandescent fumarole remained high on its SE flank, and snow rapidly melted on the S and E flanks of the cone. During the early morning of 9 January 2001, significant seismicity affected the SE flank, shaking villages and towns including Catania. Tens of thousands of people were woken by the strongest event (M 3.5, MM V). The seismic crisis ended that same day after more than 50 shocks had been registered by the monitoring network. At least three of the earthquakes measured M 3.0 or more, and several were felt by the population of a large area between Nicolosi, Fornazzo, and Catania. Cracks opened in the walls of numerous buildings, but only one uninhabited building in Zafferana partially collapsed.
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.
Source: Italy's Volcanoes