Report on Reventador (Ecuador) — 18 August-24 August 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 August-24 August 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Reventador (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 August-24 August 2021. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
IG reported that several ash emissions from Reventador during 18-24 August rose 500-1,400 m above the summit and drifted NW, W, SW, and S; sometimes weather conditions prevented visual confirmation. Seismicity was characterized by daily explosions, harmonic tremor, long-period earthquakes, and signals that indicated emissions. The Washington VAAC reported gas-and-steam and ash plumes to 1.4 km above the summit that drifted W, NW, and SW, often observed multiple times per day in satellite imagery or webcams. Nighttime crater incandescence was frequently observed, accompanied by incandescent blocks rolling down the NE, E, and S flanks as far as 600 m. A lava flow was reported traveling down the NE flank during 17-18 August.
Geological Summary. 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 Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical 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.