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Islands Connecting People and Land ‘Oki Islands Global Geopark’

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What is the Oki Islands Global Geopark?

Oki Islands Global Geopark Summary

Boundary of the Geopark

The Oki Islands Global Geopark area (indicated by the boundary line in the map below) encompasses four inhabited and many uninhabited islands located in the Sea of Japan 40-80km north of Shimane Prefecture (south-west of mainland Honshu). As isolated islands, marine life and the fisheries industry is of central importance to the way of life of the people. In consideration of this, aside from land area, the geopark also includes 1km of sea area from the coastline. The geopark has a total area of 673.5 km2 (land area 346.0 km2 and marine area 327.5 km2).


oki islands  geopark

Features of the Oki Islands Global Geopark

The land of the Oki Islands has developed through a series of stages: from being a part of the Eurasian Continent, the land sunk to the bottom of a lake on the continent, and then the bottom of a deep sea as the Sea of Japan was formed. This land then surfaced due to volcanic eruptions, and the islands were born. They later became connected to mainland Japan during the glacial ages, to eventually become the remote islands they are today. This geohistory has given birth to the unique ecosystem and cultural traditions of the Oki Region.

The islands did not become isolated by breaking off from the mainland of Japan. Rather, changes in sea level throughout history caused them to become alternately connected to the mainland and isolated islands several times throughout history. During the last glacial age 20,000 years ago, the sea level declined 130m. As the sea between the islands and the mainland is only 70m deep, the islands became connected to the mainland Shimane Peninsula. Post-glacial warming caused the sea level to rise again 10,000 years ago and the islands became isolated as they are today.

Geohistory, Unique Ecosystem, Lifestyle & Traditions

Uncover the Mysteries of the Land!

The Oki Islands Global Geopark isn't just a place where you can see precious geological heritage. It is a place that tells the story of the land, connecting the ‘Geohistory’ of the islands created over millions of years, the ‘Unique Ecosystem’ that developed on this land, and the diverse ‘Lifestyles and Traditions’ of the people that are still present today.

In the geopark there are many ‘geosites’ where you can also learn about the geology of the land as well as the ecosystem and the lifestyles of the people who live there. There is a story to be discovered at each of the geostites.

Geohistory - Sekiheki (Red Cliff)

Unique Ecosystem - Oki Salamander

Lifestyle and Traditions – Shuhaira Dengaku