Report on Reventador (Ecuador) — 15 December-21 December 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
15 December-21 December 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Reventador (Ecuador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 15 December-21 December 2004. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
On 16 December, a block lava flow from Reventador extended more than 1.5 km from the 2002 crater through a breach in the S portion of the crater wall. The flow front was ~600 m below the central vent and extended to the ESE. Lava extrusion from a vent in the crater likely began in early November, accompanied by a dramatic increase in volcano-tectonic earthquakes.
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.