IG reported a high level of activity at Sangay during 13-20 June and the seismic network recorded 327-2,190 daily explosions. Gas, steam, and ash plumes were occasionally observed in IG webcam images or described in Washington VAAC volcanic activity notifications, though weather clouds sometimes prevented observations. Ash-and-gas plumes rose as high as 1.8 km above the summit and drifted W during 13-15 June. Gas-and-steam plumes rose less than 1 km during 16-17 June. Ash plumes rose as high as 1.2 km and drifted W on 18 June. Incandescence at the summit was visible in webcam images. Overnight during 18-19 June the lava flow on the SE flank was incandescent and pyroclastic material descended the SE flank as far as 500 m several times. During 19-20 June several ash-and-gas emissions rose as high as 550 m above the summit and drifted SW. Incandescence at the summit was visible multiple times. Minor ashfall was reported in Llagos parish, Chunchi (73 km SW) on 20 June. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest 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), Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE), Washington Volcanic Ash Advisory Center (VAAC)