During 18-24 February IG reported moderate seismic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador; cloud cover often prevented visual observations. On 19 February observers confirmed the presence of a 1-km-long lava flow that had been advancing down the SW flank since 11 February. A diffuse steam plume with minor amounts of ash rose 1 km and drifted SW. On 21 February steam-and-ash emissions rose 600 m and drifted NW. Vapor plumes with minor amounts of ash rose 500 m and drifted SW on 24 February.

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.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)