Report on Etna (Italy) — 6 May-12 May 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 May-12 May 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 May-12 May 2020. 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 that on 5 May increasing and pulsating ash emissions at Etna’s New Southeast Crater (NSEC) formed a plume that drifted SSE. The activity may have concurrently occurred with the enlargement of vent number 3. Explosive activity at Voragine Crater (VOR), with minor ash emissions and occasional visible shreds of incandescent material, was relatively mild and discontinuous. During a field inspection on 8 May, volcanologists observed that the main cone was almost unchanged and produced modest ash emissions. Strong explosive activity at a cone located E of the main cone produced a lot of ash, and ejected coarse material that fell on the W edge of VOR as well as on the S terrace of Bocca Nuova Crater. Activity at NSEC again increased; on 10 May Strombolian explosions ejected material out of the crater and onto the flanks. Concurrently, increased activity in VOR was characterized by the ejection of ballistics beyond its crater rim. After a few hours Strombolian activity in NSEC significantly decreased and explosive activity in VOR was both less intense and less frequent.
Geologic Background. 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.