Report on Etna (Italy) — 7 July-13 July 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
7 July-13 July 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 July-13 July 2021. 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 continuing Strombolian activity and two episodes of lava fountaining Etna’s Southeast Crater (SEC) during 5-11 July. The first episode began at 1130 on 6 July with Strombolian activity at SEC. The intensity and frequency of explosions progressively intensified and formed lava fountains. Ash plumes rose to 1.5 km (5,000 ft) a.s.l. and drifted S, causing ashfall in areas downwind. A small lava flow originated from the S side of the cone and traveled SW, stopping at 2,800 m elevation. During fieldwork on 7 July scientist observed deposits of bombs, 1 m in diameter, on the N flank and smaller bombs scattered farther away. A second episode began at 2100 on 8 July with Strombolian activity which again intensified and formed lava fountains. Ash plumes rose to 3.4 km (11,000 ft) a.s.l. and drifted SE, causing ashfall in downwind areas. Lava flowed SW to 2,350 m elevation.
Geological Summary. 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.