Report on Reventador (Ecuador) — 23 May-29 May 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 May-29 May 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Reventador (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 23 May-29 May 2018. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
During 23-28 May IG reported a high level of seismic activity including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador. Steam, gas, and ash plumes rose 1.5 km above the crater rim and drifted NW on 23 May, and a plume of gas, water vapor, and ash rose 300 m on 26 May; cloudy weather prevented views of emissions on most days. A lava flow had advanced to 900 m on the NE flank. On 27 May incandescent blocks were observed rolling as far as 800 m down the flanks in multiple directions. An ash plume rose 3 km above the crater rim and quickly drifted W, causing ashfall in Papallacta (62 km SW), San Antonio de Pichincha (90 km W), Tabacundo (63 km WNW), Cayambe (57 km WNW), Puellaro (85 km WNW), and Puembo (80 km W).
Geologic Background. 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.