Environment Coral reefs of Kikaijima in Kagoshima now ‘Geological Heritage Site’

The coral reef terraces of Kikaijima Island in Kagoshima Prefecture have been named one of the world's 100 Geological Heritage Sites by the International Union of Geological Sciences (IUGS). Formed entirely from coral, Kikaijima has been steadily rising from the sea for roughly 100,000 years, layer by layer, preserving evidence of changing climates and shifting environmental conditions. Its unique structure serves as a natural record of the Earth's history, providing scientists with rare insight into long-term patterns of climate and sea-level change.


Researchers now hope the island will also gain official recognition as a Japanese Geopark by the Japan Geopark Committee. The International Union of Geological Sciences identifies and designates sites of outstanding global importance that help explain the Earth's formation and evolution. Every two years, an international panel of geologists and related specialists selects one hundred such locations for recognition. When the first list was announced in 2022, Japan's Genbudo Cave and the Nojima Fault in Hyōgo Prefecture were among those honoured.

Watanabe said it has long been known that the uplifting of coral reefs formed Kikaijima Island. Because well-preserved coral fossils are exposed, the island has been referred to as a "sacred place" among researchers. Watanabe and another researcher established the KIKAI research institute at the site of a former school on the island 10 years ago, and it has been accepting researchers and students ever since. Watanabe noted that people also reside on the island, which nurtures diverse cultures as well as rich natural biodiversity. Watanabe told the governor, "Anthropologists, archaeologists, sociologists and seismologists have all come to the island. Children from outside of the island have come here to study the coral reefs." Kikaijima Island is located off the coast of Kyushu, about 25 kilometres east of Amami-Oshima Island.

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