IG reported that a new eruption at Sangay began on 7 May and was continuing as of 21 May. Activity was concentrated at two eruptive centers; the Central Crater and the Ñuñurcu dome (located 190 m SSE of Central Crater). Explosive activity at Central Crater produced ash plumes that rose an average of 1 km above the crater rim and drifted W and NW. Ejected blocks rolled as far as 2.5 km down the SE flank. The Ñuñurcu dome produced a lava flow that had a maximum width of 175 m and traveled about 470 m down the SE flank. Collapses of the lava-flow front generated small pyroclastic flows and numerous block flows; one of the pyroclastic flows traveled 340 m.

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.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)