Since the Kobe Ocean Bottom Exploration Center (KOBEC) was established in 2015, it has carried out three survey voyages to the Kikai Caldera, south of Japan’s main islands. Based on these voyages, researchers have confirmed that a giant lava dome was created after the caldera-forming supereruption 7300 years ago. The dome is in the world’s largest class of post-caldera volcano, with a volume of over 32 cubic kilometers. The composition of this lava dome is different from the magma that caused the giant caldera to erupt – it shows the same chemical characteristics as the current post-caldera volcano on the nearby Satsuma Iwo-jima Island. It is possible that currently a giant magma buildup may exist under the Kikai Caldera.