During 9-15 March 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 often prevented visual observations. On 9 March an explosion at 0505 ejected blocks that fell onto the flanks 1.2 km from the crater. An explosion at 0640 produced an ash plume that rose 1 km and drifted NW. At night during 9-10 March blocks traveled 1.2 km down the flanks and a small pyroclastic flow also descended the flanks. An explosion on 10 March generated an ash-and-steam plume that rose 1 km and drifted SW. Steam-and-ash emissions were occasionally seen through cloud cover on 13 March. The next day the crater was incandescent and blocks rolled 500 m down all flanks. Steam-and-gas plumes rose 800 m and drifted NW.

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)