Global Volcanism Program | Image GVP-01225
The walls of Tiwu Nua Muri Kooh Tai, the middle of Kelimutu's three crater lakes, expose bedded hydrothermally altered rocks. Tiwu Ata Polo, the darker-colored crater lake to the SE, is visible beyond the far wall. Constant upwelling occurs at these two lakes, probably as a result of subaqueous fumaroles, directing floating sulfur in Tiwu Nua Muri Kooh Tai toward the crater walls.
Photo by L.D. Reksowirogo, 1972 (Volcanological Survey of Indonesia).