Characterization of the subsurface structure of a volcanic edifice is essential to understanding volcanic behavior. One of the best-studied volcanoes is Kīlauea (Island of Hawai‘i). Geological evidence suggests that the formation of the summit caldera of Kīlauea is cyclic, with repeated collapse followed by filling with lava. The most recent collapse occurred ca. 1500 CE, producing a basin that is several hundred meters deeper than the current caldera. In this study, we used two- and three-dimensional gravity modeling of spatially dense gravity data covering the summit area to suggest that, since its formation in 1500 CE, the caldera has...