IG-EPN reported that high levels of eruptive activity continued at Sangay during 11-18 June. Gas-and-ash plumes were visible in webcam and/or satellite images on most days rising as high as 1.5 km above the summit and drifted WNW, W, WSW, and SW. During the morning of 12 June ashfall was reported in Cebadas (35 km WNW) and Reten Ichubamba (35 km WNW), Cantón Guamote (35 km WNW), province of Chimborazo, and in the cantons of Naranjito (121 km W), Guayaquil (175 km W), Samborondón (170 km W), and Daule (185 km W), in the province of Guayas. Incandescent material at the crater was visible during the dark hours of 11-13 June, and several episodes of incandescent material traveling as far as 2.5 km down the SE flank were visible during 11-14 June. Weather conditions sometimes hindered views especially on 15 and 17 June. On 16 June seismic signals indicated lahars and increased water flow in the Upano River. Secretaría de Gestión de Riesgos (SGR) 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)