INGV reported that a thermal anomaly at Etna’s Southeast Crater (SEC) was first visible in webcam images at 0907 on 21 February, followed within an hour by weak Strombolian activity. Strombolian activity intensified and by noon lava fountaining was visible. An eruption plume had risen to 10 km above the summit and drifted SE. Lava overflowed the SEC at 1210 and traveled SW. The eruption plume reached an altitude of 12 km (39,400 ft) a.s.l., drifted SSE, and caused ashfall in Viagrande (16 km SSE), Trecastagni (16 km SE), Milo (about 11 km ESE), Aci Castello (26 km SSE), and Zafferana (10 km SE). Sometime after 1300 lava fountaining ceased, though the lava flow continued to be fed. Another flow traveling E to an elevation of 2,900 m was visible in webcam images and by scientists observing the eruption in the field. Explosivity activity ceased in the afternoon. Weather conditions hindered views over the next day but by 1900 on 22 February webcam observations were again possible. Weak Strombolian activity at SEC was visible and the E lava flow had advanced.

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)