Kelimutu

Kelimutu is a complex volcano on Flores Island in Indonesia's East Nusa Tenggara province, about 50 kilometers east of the town of Ende, part of the Sunda Arc formed by the Indo-Australian Plate subducting beneath the Eurasian Plate. Its summit reaches 1,639 meters and is elongated roughly 2 kilometers from west-northwest to east-southeast. Three crater lakes crown that summit: Tiwu Ata Bupu, the Lake of Old People, typically blue; Tiwu Ko'o Fai Nuwa Muri, the Lake of Young Men and Maidens, typically green; and Tiwu Ata Polo, the Enchanted Lake, typically red. The lakes' shifting colors come from oxidation-reduction chemistry driven by volcanic gases, sulfur dioxide and hydrogen sulfide, released through fumaroles beneath the water, and the lakes are extremely acidic, with pH recorded as low as 0.5, and range in temperature from about 21 to 30 degrees Celsius depending on volcanic activity. The most recent eruption came in June and July of 1968, a minor phreatic explosion of ash and gas with no significant lava flow. This entity documents Kelimutu specifically as a geological formation, a volcano whose three summit crater lakes change color through volcanic gas chemistry.