A crater lake is a body of water that occupies a volcanic crater or caldera. These lakes can form in the depressions left by volcanic eruptions, meteorite impacts, or explosions. Crater lakes are often used in the study of volcanic activity, geochemistry, and hydrology, as they can provide insights into the volcanic history and ongoing processes in the region.
Reference: Bacon, C. R., & Lanphere, M. A. (2006). “Eruptive History and Geochronology of Mount Mazama and the Crater Lake Region, Oregon.” Geological Society of America Bulletin, 118(11-12), 1331-1359.