AT A GLANCE
Why go?
On a quiet stretch of coast near the town of Samani in southern Hokkaido, a weathered interpretive panel marks one of the most unusual places you can stand in Japan: the spot where the Eurasian Plate and the North American Plate once collided. This is the 'Eurasian Plate Boundary' in Fuyushima — locally called Ōma — part of the UNESCO-listed Mount Apoi Global Geopark, and one of the very few sites on Earth where the seam between two continental plates is exposed openly at ground level, right beside the sea.↗↗↗
It is not a dramatic monument or a ticketed attraction, but a roadside pull-off on the old Route 336 where two utterly different kinds of rock meet. For travelers with even a mild curiosity about how the land beneath their feet was made, it offers something rare: a place to physically see, in a single view, the scar of a collision that built the Hidaka Mountains.↗↗
The seam between two worlds
The Hidaka range — the 'backbone' of southern Hokkaido — was forged when the eastern North American Plate, carrying the ancient Chishima (Kuril) island arc, shoved westward and rammed into the Eurasian Plate, thrusting up over it. Around 13 million years ago the violence of that collision forced mantle rock from 50–60 km underground all the way to the surface, producing today's Mount Apoi. The great fault line left along the join, the Hidaka Main Thrust, runs roughly 140 km north to south — yet places where that buried boundary actually breaks through to daylight are extremely scarce.
