Photo/Illutration The coral reef terraces that were designated as a Geological Heritage Site in Kikaijima island (Provided by KIKAI institute for Coral Reef Sciences)

KIKAI, Kagoshima Prefecture—The coral reef terraces of Kikaijima island here have been recognized by the International Union of Geological Sciences as one of the 100 IUGS Geological Heritage Sites.

The island is made of coral reef that has been developing and rising continuously for about 100,000 years, all the while recording the impact of environmental changes, such as climate change, in its structure.

This fact makes the island an invaluable historical source for modern researchers.

The next step is for the island to be recognized as a Japanese Geopark by the Japan Geopark Committee.

The IUGS Geological Heritage sites are important places around the world for understanding how the Earth was formed and its geologic history.

Every two years, IUGS, an international committee of geologists and other experts, selects 100 sites around the world for recognition.

IUGS's first selection of sites took place in 2022, and included Genbudo Cave and the Nojima Fault, both in Hyogo Prefecture.

Kikaijima island’s coral reef terraces and the Heisei Shinzan dacite lava dome in Nagasaki Prefecture were both recognized this year in IUGS’s second selection out of 174 nominated sites across 64 countries.

After the coral reef terraces were designated, Etsuo Kumasaki, the mayor of Kikai town, and Tsuyoshi Watanabe, the president of the KIKAI institute for Coral Reef Sciences, a nonprofit organization, presented the island’s features and characteristics at an international conference in Busan, South Korea, in late August.

They also visited the Kagoshima prefectural office on Oct. 3 to inform Kagoshima Governor Koichi Shiota of the designation.

Watanabe said it has been long known that Kikaijima island was formed by the uplifting of coral reefs. Because well-preserved coral fossils are exposed, the island has been called 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 said that people also live on the island, which nurtures diverse cultures as well as natural biodiversity.

Watanabe told the governor that, “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 kilometers east of Amami-Oshima island.

More than 10,000 people lived on the island in 1980s but that number has declined to about 6,000.

“I hope this opportunity will help more people learn about the island," Kumasaki said. "I want to take every measure to stop the decreasing population and welcome more people even if they live here temporarily.” 

The town has also started working toward being designated as a Japanese Geopark, highlighting the uniqueness of the island formed by coral reefs that have been rising for 100,000 years.

The town selected a logo through a public competition in October 2023. The town aims to submit a bid for designation as a Japanese Geopark in 2025.

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