Report on Reventador (Ecuador) — 7 May-13 May 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 May-13 May 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Reventador (Ecuador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 7 May-13 May 2003. Smithsonian Institution and US Geological Survey.
0.077°S, 77.656°W; summit elev. 3562 m
All times are local (unless otherwise noted)
Heavy rainfall (200 mm in less than 24 hours) at Reventador on 6 May led to the remobilization of ash that was deposited on the volcano's flanks during the November 2002 eruption. Lahars traveled down the volcano's SE flank via Marker and Reventador gorges. According to IG, seismic signals indicated that lahars occurred in seven main pulses, with the longest pulse lasting ~2 hours. Lahars crushed a portion of the sole petroleum pipeline in Ecuador, located on the volcano's SE flank, and dragged it 22 m. According to news reports, about 5,600 barrels of crude oil escaped the damaged pipeline and entered Reventador River. News reports also stated that a large area of the Amazon jungle was polluted. Lahars also destroyed a bridge and blocked a highway that crosses the Amazon.
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.