During 18-24 April IG reported a high level of seismic activity including explosions, volcano-tectonic events, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador; cloud cover sometimes prevented visual observations. Incandescent blocks rolled as far as 1.5 km down the flanks on most days. On 18 May a pyroclastic flow traveled 1.5 km down the SE flank, and a gas-and-ash plume rose 1.5 km above the crater. A gas-and-ash plume drifted W on 20 May, and on 24 May a pyroclastic flow traveled 1 km down the SE flank.

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)