Report on Etna (Italy) — 2 June-8 June 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
2 June-8 June 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, 2 June-8 June 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 a few eruptive episodes at Etna’s Southeast Crater (SEC) during 31 May-6 June, as well as minor and diffuse ash emissions at Bocca Nuova (BN) and ash emissions on 4 June at Northeast (NEC). Weak Strombolian activity at SEC began at 0850 on 2 June and produced minor and diffuse ash plumes. The activity intensified at 1000; within 30 minutes lava fountaining was observed and lasted for over two hours. Ash plumes rose 5-6 km (16,400-19,700 ft) a.s.l. and drifted E, causing ashfall in Petrulli, Santa Venerina, and in an areas N of Zafferana. Lava overflowed the S side of the crater and traveled W. Fountaining stopped at 1245. Weak Strombolian activity continued to be observed during the night hours of 3-4 June.
Activity increased at 1530 on 4 June and was characterized by discontinuous ash emissions and lava overflowing the S rim of SEC. Lava fountaining began at 1820 and an ash plume rose to 6.5 km (21,300 ft) a.s.l. Tephra fell in Aci Castello, Acitrezza, San Giovanni La Punta, Tremestieri, Catania, and Viagrande, and between Pedara, Fleri, and Siracusa. Fountaining began to decline at 1930. The lava flow continued to advance, and by 2300 had reached 2,800 m elevation. Occasional ash emissions were noted during 4-5 June, and the lava flow had ceased.
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.