Report on Etna (Italy) — 21 October-27 October 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 October-27 October 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 October-27 October 2020. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3320 m
All times are local (unless otherwise noted)
INGV reported that during 19-25 October activity at Etna was characterized by intra-crater Strombolian activity at Northeast Crater (NEC), Strombolian activity at the New Southeast Crater (NSEC) cone, and gas emissions at the Voragine (VOR) and Bocca Nuova (BN) craters. During a helicopter overflight along the W side on 23 October scientists observed Strombolian explosions at NSEC that produced ash emissions and ejected shreds of lava out of the crater. Both the frequency and intensity of explosions was variable. There were several thermal anomalies on the NEC crater floor, and some on the floor of the BN crater. An ash plume from NSEC rose to 4.5 km a.s.l. and drifted SSE. The report noted that, based on drone footage from the beginning of the month, the NSEC vent was 190 m long in the NW direction and 140 m wide in the NE direction.
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.