Report on Etna (Italy) — 15 March-21 March 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 15 March-21 March 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 15 March-21 March 2017. 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 during the morning of 15 March lava began to flow down the S flank of Etna's Southeast Crater (SEC) - New Southeast Crater (NSEC) cone complex. Activity rapidly intensified at 0800, and by 1000 near-constant Strombolian explosions were generating ash plumes. The lava flow reached the base of the cone and traveled S. By late afternoon the lava was advancing on top of lava flows from the previous eruption. The intensity of the Strombolian activity reached a peak around 1840-1845, and by the evening both the eruptive activity and seismicity gradually diminished. Just before midnight a new lava flow began to effuse from a vent on the S flank of the cone. On 16 March at 1243 a phreato-magmatic explosion occurred at the front of a lava flow where it contacted an area covered with snow. An INGV-Osservatorio Etneo volcanologist was injured in the explosion, suffering minor bruises. A news article noted that about 10 people were injured during the event.
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.