The IG reported that seismicity from Reventador decreased to low levels on 26 March, after the seismic network had detected an earthquake swarm the same day. On 23 April, increased seismicity was characterized by long-period events interspersed with bands of spasmodic and harmonic tremor. Observers reported that steam plumes with low ash content rose to altitudes of 5.6-6.6 km (18,400-21,700 ft) a.s.l. and drifted W. Intense noises from the volcano were also reported. A thermal anomaly and a steam plume drifting 26 km WSW were detected on satellite imagery.

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)