Report on Etna (Italy) — 17 March-23 March 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
17 March-23 March 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, 17 March-23 March 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 episodes of lava fountaining at Etna’s Southeast Crater (SEC) on 15, 17, and 19 March, though weather conditions often prevented visual observations. Strombolian activity at SEC began at 2110 on 14 March and turned into lava fountaining at 0048 on 15 March. Lava traveled towards the Valle de Bove and an eruption plume drifted E. Lava fountaining ceased by 0343 and only weak Strombolian activity followed. The lava flows continued to advance.
Weak Strombolian activity at SEC on 17 March began to intensify at 0155 and changed into lava fountaining at 0319. An eruption plume drifted SE and lava flow advanced. Fountaining activity ceased at 0717 and was followed by explosive activity. By 1859 the lava flows had reached 2,200 m elevation. Explosions at SEC and the lava flow in the Valle de Bove were visible at 2142 on 18 March when the weather conditions allowed for partial visibility of the summit.
Explosive activity at SEC was visible at 0734 on 19 March. The activity intensified at 0915 and ash emissions were visible. Lava fountaining started at 0935 and an ash plume drifted ENE. Lava fountaining activity ceased at 1136 and changed to Strombolian activity which gradually decreased; by 1350 only sporadic explosions were visible along with minor ash emissions. Lava flows were noted late in the morning.
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.