Report on Etna (Italy) — 30 June-6 July 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
30 June-6 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, 30 June-6 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 three episodes of lava fountaining at Etna’s Southeast Crater (SEC) during 28 June-4 July, producing ash plumes that rose 5-10 km (16,400-32,800 ft) a.s.l. Occasional ash-and-gas emissions rose from Bocca Nuova Crater and Northeast Crater. The first episode at SEC began with Strombolian activity at 0040 on 2 July. Ash plumes drifted ESE and within an hour lava fountains were visible that sent flows SW; fountaining ceased at 0250. The second episode began at 1656 on 4 July, produced fountains at 1725, and ended at 1900. Lava flows traveled SW and ENE, and ash plumes drifted ESE. The last episode began at 2330 on 6 July and produced ash plumes that drifted SE. Explosive activity intensified at 0000 on 7 July; lava fountaining began 30 minutes later, rose as high as 1 km, and ended within two hours. Lapilli was reported in the S part of Tremestieri and ash fell in Nicolosi, as well as in many other areas downwind. According to news articles the Catania airport was closed during the night due to ashfall.
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.