Atacazo Volcano - John Seach



0.353 S, 78.617 W
summit elevation 4463 m

Atacazo–Ninahuilca Volcanic Complex is located in the Western Cordillera of Ecuador, 10 km southwest of Quito, Ecuador. Three dacitic domes lie within the 6 km wide, 900m deep caldera. The youngest dome, Ninahuilca, erupted 2300 years ago. The eruption produced Plinian eruptions and pyroclastic flows with runout distances of 35 km.

Towns built on old eruption products, and considered to be located in high risk areas include Tambillo, Uyumbicho, Aloag, Tandapi, Canchacoto. The main Panamerican
highway, crossing the highland area from north to south, and the road leading from Aloag to Santo Domingo, linking the Northern highlands to the Coastal region are also built in a high risk area.

Typical quiescence periods at the volcano are 1000–4000 yr between eruptions, and the age of the last recognized activity (2270 years ago), the possibility of a new eruption is increasing. Future eruptions may affect areas with a population of 70,000.

Atacazo Volcano Eruptions

2300 years and 4400±35 years ago