Quilotoa (Spanish pronunciation: [kiloˈto.a]) is a water-filled crater lake and the most western volcano in the Ecuadorian Andes. The 3-kilometre (2 mi)-wide caldera was formed by the collapse of this dacite volcano following a catastrophic VEI-6 eruption about 800 years ago, which produced pyroclastic flows and lahars that reached the Pacific Ocean, and spread an airborne deposit of volcanic ash throughout the northern Andes. This last eruption followed a dormancy period of 14,000 years and is known as the 1280 Plinian eruption. The fourth (of seven) eruptive phase was phreatomagmatic, indicating that a Crater lake was already present at that time. The caldera has since accumulated a 250-metre-deep (820 ft) crater lake, which has a greenish color as a result of dissolved minerals. Fumaroles are found on the lake floor and hot springs occur on the eastern flank of the volcano.
Quilotoa is a site of growing popularity. The route to the "summit" (the small town of Quilotoa) is generally traveled by hired truck or bus from the town of Zumbahua 17 kilometres (11 mi) to the South, or more commonly by bus from Latacunga. Visitors have to pay two US dollars each to enter Quilotoa. There are a number of simple hostels in the immediate area offering services such as mules and guides. Activities include a four to five-hour hike around the caldera (whose diameter is just over 3 kilometres (2 mi)). The caldera rim is highly irregular and reaches its maximum elevations 3,810 metres (12,500 ft) to the N, 3,894 metres (12,776 ft) to the NW and 3,915 metres (12,844 ft) to the SE, at three lava domes. The 10-kilometre (6 mi) hike is sandy and steep in places and can be quite taxing, particularly if there is fog.
