INGV reported that the vents at the NE base of Etna’s SE Crater, in the Valle del Leone at about 2,800 m elevation, continued to feed lava flows during 16-22 January, though the rate notably fluctuated. Lava effusion progressively decreased during 16-17 January and had possibly ceased by the late afternoon of 17 January. Effusion restarted in the early hours of 18 January, generating two lava flows. One of the flows traveled NE along the W edge of the lava field, and the other traveled E onto the steep W wall of Valle del Bove, reaching the base of the wall on 20 January. The effusion rate decreased on 21 January and the again increased during the evening. Late on 22 January a new lava flow descended the Valle del Bove, almost reaching the base of the W wall at around 2,200 m elevation.

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.

Source: Sezione di Catania - Osservatorio Etneo (INGV)