Following several days of ash emissions from Etna's Northeast Crater, INGV-CT reported that on 14 November there was a significant increase in both the frequency and volume of ash emissions. The emissions were intermittent, alternating with periods of gas-and-steam. Ash plumes rose a few hundred meters high and drifted first SW on 14 November, then NE during 14-15 November, and finally E on 15 November.

INGV-CT staff visited the summit craters on 15 November and saw a few millimeters of brown ash on the ground mainly to the S of Northeast Crater. Ash deposits were 1 cm thick on the rim of the crater. Ash emissions were accompanied by nearly continuous deep rumblings. The vent on the crater floor was at least 75 m in diameter compared to about 25 m in October.

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)