IG-EPN reported that the eruption at Reventador was ongoing during 29 August-5 September. Seismicity was characterized by 23-48 daily explosions, long-period earthquakes, volcano-tectonic events, harmonic tremor, and tremor associated with emissions. Crater incandescence was visible overnight during 29 August-3 September; incandescent material was sometimes ejected onto the flanks and then descended as far as 500 m. Daily ash-and-gas plumes rose 600-1,000 m above the crater rim and drifted NW, W, and SW. Weather conditions sometimes prevented views of the volcano. Secretaría de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale).

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)