Heavy rainfall (200 mm in less than 24 hours) at Reventador on 6 May led to the remobilization of ash that was deposited on the volcano's flanks during the November 2002 eruption. Lahars traveled down the volcano's SE flank via Marker and Reventador gorges. According to IG, seismic signals indicated that lahars occurred in seven main pulses, with the longest pulse lasting ~2 hours. Lahars crushed a portion of the sole petroleum pipeline in Ecuador, located on the volcano's SE flank, and dragged it 22 m. According to news reports, about 5,600 barrels of crude oil escaped the damaged pipeline and entered Reventador River. News reports also stated that a large area of the Amazon jungle was polluted. Lahars also destroyed a bridge and blocked a highway that crosses the Amazon.

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.

Sources: Reuters, IRIB News, El Comercio, Instituto Geofísico-Escuela Politécnica Nacional (IG)