On 9 November, IG reported that since February Reventador began a new phase of activity characterized by lava flows from the crater, steam plumes, and thermal anomalies detected in satellite images. The lava flows traveled as far as 2 km down the N and S flanks, and steam plumes rose 200-500 m above the crater. Field visits by volcanologists in recent months confirmed that the lava dome in the crater had continued to grow above the rim, becoming the highest point of the volcano. Blocks from the lava dome and lava-flow fronts rolled down the flanks. IG noted that during 3-4 November emissions increased; a steam-and-ash plume rose 3 km above the crater. The seismic network detected an increase in the magnitude of volcanic tremor. Steam-and-gas plumes contained ash within the previous few days.

According to the Washington VAAC, the IG reported that on 9 November an ash emission from Reventador rose to an unknown height. On 13 November a gas-and-ash plume rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted SE. Ash was not detected in satellite imagery on either day.

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: Washington Volcanic Ash Advisory Center (VAAC), Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)