IG-EPN reported a high level of eruptive activity at Sangay during 9-16 January, with seismic stations recording 232-626 daily explosions. Ash-and-gas plumes were visible in both webcam and satellite images during 9-14 January, rising as high as 1.5 km above the crater rim and drifting W, WSW, and SW. On 12 January an explosion deposited incandescent material on all flanks as far as 1 km from the summit crater. At 1810 that same day a pyroclastic density current descended the SE drainage and an ash plume rose 1 km above the summit and drifted SW. Crater incandescence was sometimes visible at night, and during 11-12 and 13-14 January incandescent material was observed descending the SE drainage as far as 1 km. Cloudy weather prevented views during 15-16 January, though crater incandescence was observed overnight. Secretaría de Gestión de Riesgos maintained the Alert Level at Yellow (the second highest level on a four-color scale).

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)