IG reported moderate seismic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador during 14-20 January. Cloudy conditions occasionally obscured views of the summit. A vapor plume observed on 14 January, containing a small amount of ash, rose 1 km and drifted SW. On 15 January an explosion generated a steam-and-ash plume that rose 1 km and drifted NW. A smaller explosion produced a plume that rose 200 m. An explosion on 16 January generated an ash plume that rose 2 km and drifted SE. A vapor-and-ash plume rose 1 km and drifted SW on 19 January.

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)