IG reported that a high level of activity continued at Reventador during 30 March through 5 April, though cloudy weather conditions sometimes prevented visual observations. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose as high as 4.6 km (15,000 ft) a.s.l. and drifted mainly NW, W, and SW. As many as 68 daily explosions were detected, in addition to long-period (LP) and emission tremors. Daily thermal anomalies were also reported. On clear weather nights, incandescence could be observed in the upper part of the E flank of the volcano. Blocks were recorded rolling 400 m below the crater on all flanks during 4 April, in addition to the incandescence in the crater.

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 about 1,300 m 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 constructed a debris plain on the eastern floor of the scarp. 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)