Report on Reventador (Ecuador) — 7 November-13 November 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 November-13 November 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Reventador (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 November-13 November 2012. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
On 9 November, IG reported that since February Reventador began a new phase of activity characterized by lava flows from the crater, steam plumes, and thermal anomalies detected in satellite images. The lava flows traveled as far as 2 km down the N and S flanks, and steam plumes rose 200-500 m above the crater. Field visits by volcanologists in recent months confirmed that the lava dome in the crater had continued to grow above the rim, becoming the highest point of the volcano. Blocks from the lava dome and lava-flow fronts rolled down the flanks. IG noted that during 3-4 November emissions increased; a steam-and-ash plume rose 3 km above the crater. The seismic network detected an increase in the magnitude of volcanic tremor. Steam-and-gas plumes contained ash within the previous few days.
According to the Washington VAAC, the IG reported that on 9 November an ash emission from Reventador rose to an unknown height. On 13 November a gas-and-ash plume rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted SE. Ash was not detected in satellite imagery on either day.
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.