New observations on the recent eruptive activity of Sumaco Volcano (Ecuador), based on geochronology, stratigraphy and petrography

Sumaco is a stratovolcano located in the northern SubAndean zone of Ecuador, 105 km east of Quito. The flanks of Sumaco are jungle-covered, and scarce outcrops are found along stream banks, trails and, in quarries. Based on our field studies, eruptions of Sumaco during the historical era were associated with small-scale Strombolian activity. Earlier more robust activity, which pertains to the last 4400 years, had vigorous eruptions whose ∼10 cm thickness ash fallout deposits are identified more than 20 km from the vent.