Usu South Outer Rim Trail was added to Your Favorites!
Shikotsu-Tōya NP., Hokkaido
Claim this place to tell your story your way.
About 8,000 years ago, Usu’s summit collapsed and sent a debris avalanche toward the coast. From this trail, the lumpy “flow hills” near Usu Bay are deposits left by that ancient collapse.
Before 1977, a pond called Gin-numa and a cattle pasture filled this basin. A local family planted lotus and water lilies; schoolchildren released crucian carp. The eruption transformed that familiar outing spot into a crater.
Researchers germinated seeds from Usu’s pre-eruption soil, recovered beneath volcanic deposits 30 years after the 1977–78 eruption. The buried soil had kept a tiny seed bank alive through decades underground.
The Silver Crater is a merger: during the 1977–78 activity, 14 summit vents formed, and vents J–M joined into one large crater. The crater-side view from the trail shows the result.
Usu-Shinzan was built as magma swelled beneath the surface: during the 1977–82 activity, the summit ground rose about 180 m in places. This underground-formed dome is one of the new landforms visible from the rim.
