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Report on Reventador (Ecuador) — 12 August-18 August 2009


Reventador

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
12 August-18 August 2009
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2009. Report on Reventador (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 August-18 August 2009. Smithsonian Institution and US Geological Survey.

Weekly Report (12 August-18 August 2009)

Reventador

Ecuador

0.077°S, 77.656°W; summit elev. 3562 m

All times are local (unless otherwise noted)


The IG reported that seismic tremor from Reventador was sporadically detected during 21 July-3 August. On 4 August, seismicity increased and periods of tremor frequently saturated the seismic stations. Thermal anomalies detected in satellite imagery on 1 and 2 August became more intense on 4, 5, and 10 August. On 6 August, a steam plume rose 1.2 km above the crater and drifted W. Incandescent blocks were ejected from the crater and fell onto the flanks. Thermal images taken from a location 7 km E of Reventador revealed a linear area of higher temperatures, confirming the presence of a new lava flow on the S flank. Incandescence in the crater was seen during observations on 9 August. According to the Washington VAAC, IG reported that an ash plume rose to an altitude of 3.6 km (11,700 ft) a.s.l. and drifted NW on 15 August.

Geological Summary. Volcán El 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 stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor about 1,300 m to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the scarp. The largest recorded 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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)