Report on Etna (Italy) — 3 March-9 March 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
3 March-9 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, 3 March-9 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 2, 4, and 7 March. Weak Strombolian activity began at SEC at 1145 on 2 March, then intensified at 1234 and produced an ash plume. Lava fountaining began at 1324. Ash plumes rose to 9 km above the summit and drifted S, causing lapilli to fall in Nicolosi (16 km S), Aci San Antonio (18 km SE), Pedara (15 km SSE), and Catania (29 km SSE). Lava fountaining ceased at 1550, ending the eighth episode.
The ninth episode began at the SEC as weak Strombolian at 0120 on 4 March. Ash emissions were visible at 0200 but dispersed quickly. Strombolian activity at Voragine (VOR) was also visible with ejected material rising above the crater rim. Lava fountaining began at SEC at 0320, but by 0515 the activity had decreased. Lava flows that advanced towards the Valle de Bove were fed by spattering and a new vent that opened at the E base of the SEC. Strombolian activity at VOR changed to 300-m-tall lava fountaining at 0850. Ash plumes rose 11 km above the summit and caused lapilli to fall in Fiumefreddo (19 km ENE), Linguaglossa (17 km NE), and the area of Reggio Calabria.
The tenth episode began with Strombolian explosions at SEC and minor lava effusion at the new vent at the E base of SEC during the first hour on 7 March. Strombolian activity intensified at 0430; an eruption plume rose 5 km above the summit and drifted E. Lava overflowed the SEC onto the E flank and expanded into the Valle de Bove, reaching an elevation of 2,800 m by 0450. Strombolian activity again intensified beginning at 0520 and the lava flow advanced to 2,700 m elevation. Lava fountaining started at 0720 and ended at 0810. An eruption plume rose 10 km and drifted E. Ash and lapilli fell in Milo (11 km ESE), Fornazzo (10 km ESE), Trepunti (17 km ESE), Giarre (17 km ESE), Macchia di Giarre (16 km ESE), Mascali (18 km E), Riposto (19 km ESE), and Torre Archirafi (20 km ESE). Strombolian activity resumed at 1050 and was over by 1500.
Strombolian activity at SEC returned at 1914 on 9 March. Lava overflowed the crater at 2013 and advanced towards the Valle de Bove. Strombolian activity increased at 2100 and ash emissions drifted NE. The lava flow reached 2,900 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.