Quilotoa is a truncated, dacitic cone in the Western Cordillera of Ecuador, 35 km WNW of the city of Latacunga, that contains a 3-km-wide caldera with steep-sided walls that rise 400 m above the surface of 240-m-deep caldera lake. Multiple lava domes are present along the caldera's perimeter. This small volcano has produced eight major explosive eruptions during the past 200,000 years. Its most recent major eruption about 800 radiocarbon years ago produced voluminous pyroclastic flows, lahars that reached the Pacific Ocean, and one of the largest airfall-tephra deposits of the northern Andes. Formation of the caldera was followed by extrusion of a small lava dome. Reports of observed eruptions from the caldera lake are somewhat ambiguous. Fumaroles are present on the lake floor and hot springs occur on the E flank.