[4] The caldera contributed to an eruption which has been dated to about 100,000 years before present (range by various techniques mostly fall 100,000 to 109,000) that generated the Ata tephra in southern Japan.

[1] This southern caldera first had the Ata name but is not believed now to be associated with the vents of the major eruption of 100,000 years ago.

[2] The National Catalogue of the Active Volcanoes of Japan (JMA, 2013) included features of the Ibusuki Volcanic Field as part of the Ata post-caldera system.

[3] By this definition the single caldera may be a rounded triangle about 30km in length and up to 25km in width,[1] although the usual quoted size is smaller.

[7] The alignment extends all the way north past Mount Kirishima to intersect the Aso Caldera by gravitational anomaly.