Report on Nevado del Huila (Colombia) — 25 November-1 December 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 November-1 December 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2009. Report on Nevado del Huila (Colombia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 November-1 December 2009. Smithsonian Institution and US Geological Survey.
Nevado del Huila
2.93°N, 76.03°W; summit elev. 5364 m
All times are local (unless otherwise noted)
INGEOMINAS reported that during 25 November-1 December gas plumes from Nevado del Huila were seen on the web camera rising 8.4 km (27,600 ft) a.s.l. and drifting downwind. Seismicity included both tremor indicative of gas emissions and hybrid earthquakes. An overflight on 25 November revealed that the newest lava dome had continued to grow. Based on pilot observations, the Washington VAAC reported that on 26 November a gas plume, possibly containing ash, rose to an altitude of 7.6 km (25,000 ft) a.s.l. Ash was not identified in satellite imagery, although low weather clouds were present in the area. A sulfur dioxide plume was emitted on 30 November at a calculated rate of 3,900 tons per day. The Alert Level remained at II (Orange; "probable eruption in term of days or weeks").
Geologic Background. Nevado del Huila, the highest peak in the Colombian Andes, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. The high point of the complex is Pico Central. Two glacier-free lava domes lie at the southern end of the volcanic complex. The first historical activity was an explosive eruption in the mid-16th century. Long-term, persistent steam columns had risen from Pico Central prior to the next eruption in 2007, when explosive activity was accompanied by damaging mudflows.