Report on Sangay (Ecuador) — February 2011
Bulletin of the Global Volcanism Network, vol. 36, no. 1 (February 2011)
Managing Editor: Richard Wunderman.
Sangay (Ecuador) Many plumes seen by pilots during past year ending February 2011
Please cite this report as:
Global Volcanism Program, 2011. Report on Sangay (Ecuador). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 36:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN201102-352090.
2.005°S, 78.341°W; summit elev. 5286 m
All times are local (unless otherwise noted)
The last report discussed observations of ash plumes and MODVOLC thermal alerts at Sangay through February 2010 (BGVN 35:01). Intermittent reporting indicated that similar activity continued through at least February 2011, with plumes reaching up to 7.6 km altitude (table 7). Clouds obscured the view at times, and plumes were reported primarily by pilots and were sometimes visible on satellite imagery.
|Date||Type of plume||Altitude||Distance and direction||Source|
|21 Apr 2010||Ash||6.7 km||--||Pilot observation|
|06 May 2010||Ash||--||--||Pilot observation|
|06 May 2010||Ash||--||W||Pilot observation and satellite imagery|
|22-23 Jul 2010||Diffuse plumes||--||65-115 km W||Pilot observation and satellite imagery|
|21 and 23 Jul 2010||Occasional thermal anomalies||--||--||Satellite imagery|
|19 Aug 2010||Ash-and-gas plumes, intermittent thermal anomalies||--||25 km W||Satellite imagery|
|20 Aug 2010||Emission||--||--||Pilot observation|
|30 Aug 2010||Ash||--||--||Pilot observation (near Sangay)|
|05 Sep 2010||Ash||5.5 km||--||Pilot observation|
|10 Sep 2010||Small plume and thermal anomaly||--||--||Satellite imagery|
|13 Sep 2010||Gas with possible ash and a thermal anomaly||--||W||Tegucigalpa Meteorological Watch Office (MWO) (Honduras), pilot observation, and satellite imagery|
|21 Sep 2010||Ash||7.6 km||--||Pilot observation|
|06 Oct 2010||Small ash clouds||--||WNW||Pilot observation and satellite imagery|
|14 Oct 2010||Pilot reported ash, only gas plumes drifting NW observed in satellite imagery||--||NW||Pilot observation and satellite imagery|
|29 Oct 2010||Steam and gas plume possibly with ash and a thermal anomaly||--||--||Satellite imagery|
|05 Dec 2010||Ash||--||--||Guayaquil MWO (Ecuador)|
|12 Jan 2011||Ash and thermal anomaly||6.7 km||>45 km SW||Pilot observation and satellite imagery|
|20 Jan 2011||Ash||7.6 km||--||Pilot observation|
|27 Jan 2011||Small ash clouds||--||N||Satellite imagery|
|23 Feb 2011||Pilot reported ash, small cloud drifting NW in satellite imagery with no ash confirmed||--||SSE||Pilot observation and satellite imagery|
On 5 December 2010, the Washington Volcanic Ash Advisory Center (VAAC) stated that Instituto Geofisico reported elevated seismicity.
The MODVOLC alert system issued thermal alerts for Sangay monthly during March 2010 through early October 2010. Then, alerts were absent until 11 January 2011 (table 8).
|Date (UTC)||Time (UTC)||Pixels||Satellite|
|15 Mar 2010||0330||1||Terra|
|30 Apr 2010||0345||1||Terra|
|16 May 2010||0345||1||Terra|
|03 Jun 2010||0330||1||Terra|
|12 Jul 2010||0340||1||Terra|
|18 Aug 2010||0655||1||Aqua|
|28 Sep 2010||0650||2||Aqua|
|30 Sep 2010||0335||1||Terra|
|02 Oct 2010||0325||1||Terra|
|07 Oct 2010||0345||1||Terra|
|11 Jan 2011||0345||1||Terra|
|02 Mar 2011||0330||1||Terra|
Geologic Background. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.
Information Contacts: Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).