Lake Coatepeque: A Blue Caldera Seen from the ISS

NASA’s Earth Observatory highlights Lake Coatepeque in El Salvador, a blue caldera lake formed by ancient eruptions. A February 10, 2026 ISS image captures the surrounding volcanic landscape and the caldera’s rim near Santa Ana; while Santa Ana remains active, Coatepeque has had no eruptions in the Holocene. The lake’s sometimes turquoise color is linked to natural mineralization and pigments from microalgae/cyanobacteria. The image, taken with a Nikon Z9, illustrates the Central American Volcanic Arc and the human development around the lake.