One of the biggest of these domes collapsed leaving a caldera that in time filled with water and transformed into a freshwater lake capable of sustaining life.

Solfataras (fumaroles that emits sulfuric gases) occurring on its southwest rim is evident that under this lake is a sleeping active volcano.

Active solfataras, fumaroles, and hot springs are also found in the Amacan-Gopod thermal area south of the lake.

The edge of the lake is badly silted as a result of human activities on the upper slopes of the watershed, particularly road construction, shifting cultivation and logging.

The disposal of mine tailings is also having a direct adverse impact on the lake's resources.