Report on Reventador (Ecuador) — 23 July-29 July 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 July-29 July 2008
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Reventador (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 23 July-29 July 2008. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
The IG reported that the number of earthquakes per day from Reventador increased during July and were the greatest on 24 and 25 July. At 1500 on 27 July, continuous seismic tremor was registered and was followed by observations of incandescence around the crater. Thermal anomalies were also identified on satellite imagery. At 1900 explosions produced ash plumes and ejected incandescent material that fell onto and rolled down the flanks. On 28 July, ash plumes drifted NW and W. Ashfall was reported in Olmedo, about 50 km NW. Later that day, ash plumes rose to altitudes of 4-6 km (13,100-19,700 ft) a.s.l. and drifted NW. On 29 July, steam plumes rose from the crater and drifted NW. A sulfur smell was reported at areas around the volcano. A lava flow traveled S.
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.