Report on Etna (Italy) — 13 February-19 February 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 February-19 February 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Etna (Italy). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 13 February-19 February 2019. Smithsonian Institution and US Geological Survey.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
On 19 February INGV summarized Etna’s fissure eruption that occurred high on the SE flank during 24-27 December 2018, noting that 3-4 million cubic meters of lava erupted and covered an area of 1 square kilometer. After the event seismicity gradually decreased. The last significant event was a ML 4.1 recorded on 8 January 2019; afterwards seismicity was characterized as frequent events with modest magnitudes. Since the beginning of January ash emissions intermittently rose mainly from Northeast Crater (NEC) and more sporadically from Bocca Nuova. News sources noted that the Catania Airport (Aeroporto di Catania – Sicilia) was closed during 26-27 January. Preliminary assessments of some of the ash deposits showed they contained no juvenile material. During 11-17 February ash emissions of variable intensity rose from NEC and were notable on 14 and 18 February. Volcanic tremor amplitude did not significantly vary compared to the previous week, having average values overall. The Catania Airport announced the partial closure of airspace and flight delays during 17-18 February due to ash emissions.
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.