During 20-26 August IG reported moderate to high volcanic activity at Reventador, including explosions, long-period earthquakes, harmonic tremor, and tremor. On 20 August ash plumes, observed through partly cloudy skies, remained near the volcano. On 26 August in the morning hours emissions of water vapor were reported above the crater drifting SW. The volcano was obscured by clouds the other days of the week. On 24 August the Washington VAAC reported an emission with light ash to 6 km (20,000 ft) a.s.l. identified by wind and satellite data, seismic detection, and pilot report.

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.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)