Global Volcanism Program | Image GVP-10483
Lake Atitlán fills the northern part of the Atitlán caldera complex. The caldera formed in three stages: Atitlán I caldera about 11 million years ago (Ma), Atitlán II caldera about 8 Ma, and Atitlán III caldera about 84,000 years ago. The southern margin of the first caldera lies near the southern shore of the 18-km-wide lake, San Pedro and Tolimán volcanoes were constructed over the southern margin of the second caldera, and Atitlán over the third.
NASA Landsat image, 2000 (courtesy of Loren Siebert, University of Akron).