Abstract
A gravimeter survey was made on the frozen surface of the gigantic caldera lake, Kuttyaro. A Gravity low, reaching -46 milligals, was found, with iso-anomaly contour lines conforming the caldera shape. A layer of coarse pumice thickening toward the centre is required to account for the observed anomalies. This is compatible with volcanological inferences. Gravity anomaly distributions at several other calderas are discussed also.
