During 15-21 July IG reported a high level of seismic activity including explosions, tremor, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador; cloud cover often prevented visual observations. On 14 July a steam-and-ash plume rose 1 km and drifted W, and on 16 July an ash plume rose 1.3 km and drifted NW. On 17 July an ash plume rose 700 m, and light gray deposits possibly from a pyroclastic flow were observed. On 20 July explosions produced ash plumes that rose 1 km and drifted NW. The next day a steam-and-ash plume rose 1.5 km and drifted E. Explosions ejected incandescent material onto the flanks.

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)