Based on increased volcanic tremor, INGV reported that weak Strombolian activity and emissions of lava and ash from the SE Crater of Etna occurred on 6 December. Later that day, seismicity dropped and explosive activity stopped. On 11 December, INGV monitoring cameras recorded Strombolian activity that resumed from a pit on the SE Crater, following a weak increase of seismicity. Lava was emitted continuously from the E flank of the SE Crater since 13 October. Lava also flowed from a vent at 2800 m elevation on the W headwall of the Valle del Bove. The eruption and lava flows from the 2800-m vent finished on 15 December. The Toulouse VAAC reported that a diffuse plume possibly containing ash was intermittently visible from a webcam on 13 December, drifting E.

Geological Summary. Mount Etna, towering above Catania on the island of Sicily, has one of the world's longest documented records of 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 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.

Sources: Sezione di Catania - Osservatorio Etneo (INGV), Toulouse Volcanic Ash Advisory Centre (VAAC)