Report on Reventador (Ecuador) — 5 November-11 November 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 November-11 November 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, 5 November-11 November 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 SOTE (Sistema de Oleoducto Transecuatoriano) personnel and residents near Reventador observed incandescence in the crater on 7 November. The reports were confirmed by the presence of thermal anomalies in satellite imagery. The next day, seismicity increased and a steam-and-ash plume rose to an approximate altitude of 5.6 km (18,400 ft) a.s.l. and drifted SW. Incandescent blocks were ejected from the inner crater to the S. Residents in El Chaco (about 35 km SE) and in the Quijos area heard strong explosions and saw steam plumes with low ash content. A pilot reported that a steam plume with little ash content at an altitude of 7.6 km (25,000 ft) a.s.l. drifted NW. On 9 November incandescent blocks were ejected 100 m into the air, and roaring and "cannon shot" sounds were reported. Strombolian activity and two lava flows that descended the N and S flanks of the central cone were observed using a permanent camera. Slight ashfall was noted in Cayambe, about 55 km WNW. A thermal anomaly was detected by satellite imagery on 9 and 10 November. On 10 November, seismicity considerably decreased and gas emissions continued. The lava flows continued to advance.
According to a news article, officials suspended flights into Quito airport due to ash plumes on 10 November for three hours as a preventative measure.
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.