During 12-16 November, seismic and volcanic activity continued at Reventador. Constant tremor, and hybrid and volcanotectonic earthquakes were recorded. On 12 November a column of steam and ash was seen rising 6-7 km above the volcano and drifting to the W. There was only a moderate amount of ash in the cloud, therefore there was not much ashfall. Mudflows traveled down Reventador's flanks and during several evenings incandescence was visible on the NE flank. During a flight over the volcano on the 18th, a lava flow was seen on the crater's S wall advancing slowly. Also, pyroclastic-flow deposits were seen that IG warned may be remobilized during heavy rain, becoming dangerous mud flows.

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 about 1,300 m 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 constructed a debris plain on the eastern floor of the scarp. 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.

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