Kawah Ijen acid lake, Volcanic crater lake in East Java, Indonesia
Kawah Ijen is a crater lake within the Ijen volcano complex in East Java, distinguished by its striking turquoise water and considerable depth. The lake sits within a volcanic crater at high elevation, surrounded by steep walls that allow for sulfur extraction activities.
The crater lake formed through volcanic activity, with its last major magmatic eruption occurring in 1817. Since then, smaller volcanic events continued to affect the region into the 21st century.
Sulfur mining has been a livelihood for local communities for generations, with workers descending into the crater to extract and carry the mineral. This labor defines the daily rhythm of the villages surrounding the volcano.
A visit requires a nighttime hike to the crater to witness the striking blue flames from burning sulfur gases. The climb is demanding and requires good physical fitness along with appropriate gear for dark and potentially harsh conditions.
The lake's water is extremely acidic with a pH level near zero, representing one of the highest acid concentrations found anywhere. This extreme acidity means almost no life exists in the water itself, creating an otherworldly and unforgettable environment.
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