Report on Sangay (Ecuador) — 27 March-2 April 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 March-2 April 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Sangay (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 March-2 April 2019. 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 renewed activity at Sangay on 26 March based on satellite data and a Washington VAAC notice of ash. According to the VAAC a small ash plume rose less than 1 km above the crater rim and drifted SW. Seismicity had decreased to an average of three events per day after the last eruption ended on 7 December 2018, and then to 1 event per day during the past month. There was no seismic record of the 26 March event due to technical difficulties.
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.