Mount Onamedake was added to Your Favorites!
Towada-Hachimantai NP, Akita
Claim this place to tell your story your way.
Between 8,400 and 7,500 years ago, eruptions built Onamedake’s scoria cone and sent lava over the rim of an older crater at Katakura—a younger summit laid across an older landscape.
On the mountain’s shifting volcanic scree, komakusa anchors itself with roots over 1 m long. Nearby, sticky-leaved butterwort catches tiny insects to supplement nutrients in poor soil.
A horse-shaped patch of spring snow is said to explain “Komagatake” (“Horse Peak”). In local lore, the horse faces Nanbu (Iwate), while its droppings promise fertile fields in Akita.
Akita-Komagatake is a cluster of peaks, not one simple cone: 2 adjoining calderas shape its summit area. Onamedake rises inside the northern basin, now largely filled by younger volcanic cones and lava.
Akita-Komagatake’s last magmatic eruption did not come from Onamedake: neighboring 女岳 (Medake) erupted from September 1970 to January 1971, sending out lava in repeated bursts.
Onamedake’s 1,637-m summit supports a “false alpine zone”: deep snow and fierce winds let alpine plants thrive lower than they do in many other parts of Japan. This summit belt became a National Natural Monument in 1926.
