Mount Kelimutu

Mount Kelimutu is one of the most enigmatic geological wonders on the planet. Located in the central spine of Flores Island, Indonesia, this dormant volcano is world-famous for its three crater lakes, each of which displays a different, intensely vivid color—and each of which changes color independently of the others. It is a place where geology meets spirituality, creating a landscape that feels surreal and otherworldly.

The Three Lakes of Souls

The local Lio people have a deep spiritual connection to the lakes. They believe that Kelimutu is the final resting place for the souls of the dead.

1. Tiwu Ata Mbupu (Lake of Old People): Located on the westernmost side, this lake is historically blue or white. It is where the souls of those who died of old age and lived a righteous life go to rest. It is separated from the other two lakes by a thin crater wall.
2. Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Maidens): This central lake is traditionally green or turquoise. It is the abode of the souls of young people who died prematurely. The vibrant green color represents the vitality of youth cut short.
3. Tiwu Ata Polo (Bewitched or Enchanted Lake): The easternmost lake is often a deep, blood-red or dark brown. This is the place for the souls of the wicked—murderers, thieves, and those who committed crimes in life. The red color is visibly linked to the “blood” of their sins.

The Chemistry of Color

The science behind the color shifting is complex and fascinating.

• A Chemical Soup: The lakes are essentially massive pools of dilute acid. Volcanic gases (sulfur dioxide, hydrogen chloride) rise from subaqueous fumaroles at the bottom of the lakes, dissolving into the water.
• Oxidation States: The color depends largely on the oxidation state of the dissolved minerals, particularly iron and manganese.
  • Green/Blue: Indicates a more reduced state (less oxygen), often rich in ferrous iron ($Fe^{2+}$).
  • Red/Brown: Indicates an oxidized state (more oxygen), forming ferric iron ($Fe^{3+}$), which is essentially rust suspended in the water.
• Independence: What makes Kelimutu unique is that each lake has its own separate “plumbing” system. Even though they are only separated by thin walls of rock, the gas input and groundwater interaction for each lake differ, allowing one to be turquoise while its neighbor is blood red.

The Pati Ka Ritual

Every year in August, the Lio people gather at the summit for the Pati Ka festival (“Feeding”).

• Offerings: The community elders, known as Mosalaki, lead a procession to the crater rim. They bring offerings of rice, betel nuts, tobacco, and meat (fork and chicken) to feed the spirits of the ancestors.
• Communing: The ritual is a way to ask for blessings, rain for the crops, and harmony for the community. It reinforces the belief that the dead are not gone but are living in a parallel existence within the waters of the volcano.
• Tourism Balance: The festival is now a major tourist attraction, but park authorities work hard to ensure that the influx of visitors does not disrupt the solemnity of the ceremony.

The Guardians of the Lakes

The cultural connection to Kelimutu is maintained by the Mosalaki.

• The Keepers: The Mosalaki are the traditional elders of the Lio people. They are the only ones authorized to lead ceremonies at the crater rim. They serve as intermediaries between the living community and the spirits of the ancestors residing in the lakes.
• The Color Prophecy: The elders believe that a change in the color of the lakes is a portent. For example, if the Tiwu Ata Polo (Enchanted Lake) turns a darker, muddier red, it is seen as a sign of looming social unrest or a bad harvest. This traditional knowledge often predates scientific monitoring, serving as a cultural early warning system.
• Sacred Geography: The entire mountain is zoned. There are areas where tourists can walk, and “forbidden zones” (fai) where only the Mosalaki can enter during specific lunar cycles to perform cleansing rituals.

The “Baffle” Theory

Geologists have long puzzled over how three lakes so close together can have such different chemistries.

• The Plumbing: The leading theory is that although the lakes share a deep magma source, the “plumbing” system near the surface is separated by hydrothermal “baffles.”
• Mineral Sealing: Over centuries, minerals precipitating from the hot water have sealed the cracks in the rock walls between the craters. This creates three distinct, watertight basins.
• Gas Injection: Each basin receives a different mix of volcanic gas. One might get more Hydrogen Sulfide ($H_2S$), turning it green, while another gets more Hydrogen Chloride ($HCl$), making it acidic enough to dissolve iron rocks and turn red. If a major earthquake were to crack these baffles, the lakes could mix, potentially triggering a massive phreatic explosion.

Biodiversity: The Singing Forest

The Kelimutu National Park is an island of biodiversity.

• The Wallacea Scops Owl: The park is one of the few places to hear the call of the Flores Scops Owl (Otus alfredi). This small, elusive bird was thought to be extinct for a century until it was rediscovered in these montane forests.
• The Bare-Throated Whistler: Another endemic bird, the Bare-throated Whistler (Pachycephala nudigula), is famous for its loud, melodious song that “whistles” through the mist at dawn, providing a natural soundtrack for hikers ascending the peak.
• Flora: The slopes are covered in Casuarina trees and Rhododendron renschianum, a rare rhododendron found only at high altitudes in Nusa Tenggara. These plants have adapted to the acidic soil conditions created by the constant volcanic degassing.

Tourism: The Dawn Trek

Visiting Kelimutu is a highlight of any trip to Flores.

• The Journey: Most travelers stay in the village of Moni at the base of the mountain. The trek usually begins at 4:30 AM to catch the sunrise.
• The Reveal: As the sun breaks over the horizon, the mist that usually shrouds the craters begins to lift. The colors of the lakes become visible one by one—a slow, dramatic reveal that is photographer’s dream. It is worth noting that for the best visibility, visiting during the dry season (July-August) is highly recommended, as the crater rim can be socked in by thick clouds for days at a time during the monsoon.
• The Monkeys: The forest path leading to the summit is inhabited by long-tailed macaques. These intelligent monkeys often follow hikers, hoping for a snack. They are part of the protected ecosystem of Kelimutu National Park, which also hosts rare birds like the Wallacea Owl.

The Fabric of Culture: Ikat

The colors of Kelimutu are woven into the very fabric of Lio culture.

• Natural Dyes: The Lio people are famous for their Ikat weaving. Traditionally, the dyes were sourced from local plants—indigo for blue, morinda root for red. The weavers often say that the “spirit of the color” comes from the same earth forces that paint the crater lakes.
• Motifs: The patterns in the Lawo (sarongs) often feature jagged lines representing the mountains and circular motifs representing the lakes. Wearing these textiles during the Pati Ka ceremony is a way of physically connecting the human body to the sacred geography of the volcano.

Volcanic Agriculture: The Coffee Connection

The slopes of Kelimutu are not just spiritual; they are productive.

• Flores Bajawa Coffee: The volcanic ash from Kelimutu and its neighbors has created an Andosol soil profile that is perfect for growing Arabica coffee. The high altitude (1,200m+) and the cool mists contribute to the beans’ complex flavor profile (often described as chocolatey and floral).
• Eco-Tourism Synergy: Many tourists who come for the lakes stay for the coffee. Visits to the local plantations support the village economy and provide an incentive to protect the forest cover, which prevents landslides and maintains the watershed for the crater lakes.

Geological Future

While Kelimutu has not erupted magmatically in historic times (its last major eruption was phreatic in 1968), it is still considered active.

• Wall Stability: The partition walls separating the lakes are steep and unstable. A major earthquake or a sudden increase in hydrothermal pressure could breach these walls, mixing the lakes.
• Phreatic Threat: The main danger is a phreatic explosion—a sudden blast of steam caused by superheated groundwater flashing to steam. This unpredictable hazard means that visitors must always respect the safety railings and warning signs.

Conclusion

Kelimutu is a place where the veil between the physical and the spiritual seems thin. Whether viewed through the lens of a geochemist analyzing mineral suspension or a Lio elder communing with ancestors, it remains a site of profound power and mystery. It is a living, breathing painting created by the fire of the earth.