Report on Sangay (Ecuador) — 27 October-2 November 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
27 October-2 November 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Sangay (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 October-2 November 2021. Smithsonian Institution and US Geological Survey.
2.005°S, 78.341°W; summit elev. 5286 m
All times are local (unless otherwise noted)
IG reported a high level of activity at Sangay during 27 October-2 November. Seismicity was characterized by 120-175 daily explosions, long-period earthquakes, lahar events, and signals indicating emissions. Weather clouds and rain often prevented visual and webcam observations of the volcano, though almost daily ash-and-gas plumes were identified in satellite images by the Washington VAAC or in webcam views; plumes rose 570-2,000 m above the volcano and drifted N, NW, W, and SW. Thermal anomalies over the volcano were often visible in satellite data. Incandescent material was observed descending the SE flank on 31 October.
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 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.