According to the Washington VAAC, satellite imagery on 2 December showed an ash plume from Reventador at a height of ~5 km extending W of the volcano. Also, IG reported to the VAAC that ash was seen drifting NW on 4 December. A hot spot was visible on infrared satellite imagery. On 4 December, Strombolian activity was seen in Reventador's crater. Since 9 November, volcanic material continued to gradually fill the crater and generate a lava flow down one flank. Activity was accompanied by a gas column that reached a maximum height of 3 km.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Washington Volcanic Ash Advisory Center (VAAC)

Geological Summary. Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.