Ash plumes were reported between October 2006 and December 2007 (BGVN 33:03). Thermal anomalies have been detected between 27 March and 4 December 2008 (table 2). A minor ash plume was seen on satellite imagery and by pilots drifting WNW on 24 September 2008.

Table 2. Thermal anomalies at Sangay based on MODIS-MODVOLC imaging during 1 January to 19 October 2008 (continued from the list in BGVN 33:03). No thermal anomalies were noted in 2008 prior to 27 March. Courtesy of Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System.

Geological Summary. 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 the open 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 eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost 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, 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) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).