The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that eruptive activity continued at Reventador during 11-18 March. Seismicity included 59-106 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Multiple daily ash-and-gas plumes rose as high as 1.1 km above the crater rim and drifted in multiple directions. Webcams recorded multiple instances nightly of incandescent material descending the flanks as far as 900 m below the crater rim. Minor ashfall was reported in Piedra Fina, 8 km SE, at around 0700 on 14 March; ashfall in that area had been persistent for the past few months. On 17 March a pyroclastic flow traveled 400 m down the SE flank. Incandescent material was ejected 400 m above the crater rim. 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)