IG reported moderate seismic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador during 28 January-3 February. Cloudy conditions obscured views of the summit most of the time. On 28 January a steam plume with low ash content rose 1 km above the crater and drifted W. During 29-30 January steam plumes with minor amounts of ash rose 400-500 m and drifted SW and S.

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)