IG reported that during 17-19 July seismic activity at Reventador remained high; at times periods of increased seismicity were followed by relatively quiet episodes. The seismic network recorded long-period signals, rockfalls, explosions, and emissions. Based on reports from observers at camp San Rafael, cloud cover often prevented visual observations, although on 18 July a new lava flow on the E flank was observed with a video camera, and a gas-and-ash plume was observed rising 1 km. During 21-22 July gas plumes with low ash content rose to low heights.

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)