Geologic Background:
This isolated composite cone east of the Andean
crest is one of Ecuador's most active volcanoes having
been in frequent eruption for the past several centuries.
The steep-sided, glacier-covered volcano grew within
horseshoe-shaped calderas of two previous edifices, which
were destroyed by collapse to the east. Sangay towers
above the tropical jungle on the east side; on the other
sides flat plains of ash from the volcano have been
sculpted by heavy rains into steep-walled canyons up to
600 m deep.
Historic Activity:
- It has been in frequent eruption for the past several
centuries.
- The earliest report of an historical eruption was in
1628.
- More or less continuous eruptions took place from
1728 until 1916, and again from 1934 to the present.
Recent Activity:
- Explosions began in early August 1988 and a new lava
flow was reported August 11.
- During a visit to Sangay during Nov. 24 to Dec. 12,
1995 phreatic explosions, blue gas plumes, crater glow
and dome rockfalls were observed
Data Sources:
- Smithsonian's SEAN Bulletin (V. 1, No. 10; V. 8, No.
7; and V. 13, No. 8)
- Global Volcanism Network (V. 21, No. 3 ).
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