The Oki Islands underwent various changes through time. We will explain the geohistory of this land—the origins of the unique ecosystem that is rare even from a global perspective, and of the local history and culture.
250 million years ago (Permian–Triassic)
Oki Islands were once part of the continent
26–6 million years ago (Neogene)
Sea of Japan Formation Period
From the "bottom of a lake" to the "bottom of a sea"
6 million–400 thousand years ago (Neogene–Quaternary )
Volcanic Islands Period
Powerful eruptions and the birth of the Oki Islands
400 thousand years ago–present
From a Peninsula to Remote Islands
Separation from Japan's main Honshu island and the present Oki Islands