Report on Etna (Italy) — 10 March-16 March 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
10 March-16 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, 10 March-16 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 9 and 12 March. The eleventh episode began with Strombolian activity at SEC observed at 1914 on 9 March. Just after midnight activity quickly intensified with lava fountaining and a large eruption plume that rose at least 9 km a.s.l. The plume drifted ENE and caused ash and lapilli to fall in Mascali (18 km E), Giarre (17 km ESE), and Fiumefreddo (19 km ENE). Lava reached an elevation of 1,800 m, also effusing from the flank of the S vent. Lava fountaining ceased at 0430 on 10 March and sporadic ash emissions continued until 0700.
The twelfth episode began at 0630 on 12 March with Strombolian activity at SEC and ash emissions. The activity intensified at 0754 and lava overflowed the E part of SEC, traveling towards the Valle de Bove. Lava fountaining began at 0841, with jets up to 500 m, and an eruption plume rose 6 km a.s.l. and drifted E. Lava advanced to 2,800 m elevation and within another hour had reached 2,000 m elevation. At 0939 the plume had risen 9-10 km and had caused ashfall in Milo and Fornazzo (10 km E), Giarre, Santa Venerina (15 km SE), and Torre Archirafi (20 km ESE). Lava fountaining ceased at 1050, though weak Strombolian activity and ash emissions continued until 1115. The lava flow advanced as far as 1,700 m elevation and a second lava flow expanded SE on the W slope of the Valle del Bove, stopping at 3,000 m a.s.l.
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.