Mount Mihara, Hachijojima was added to Your Favorites!
Fuji-Hakone-Izu NP, Tokyo
Claim this place to tell your story your way.
Hachijojima’s gourd shape comes from 2 joined volcanoes. Older Mihara was active from about 100,000 to 3,700 years ago; the island’s other volcano is Hachijo Fuji, on the northwest side.
Near Mihara’s summit, Koike and Oike—“Small Pond” and “Big Pond”—are said to be remnants of a lake that filled the caldera until about 6,000 years ago.
At 36 m, Karataki is Hachijojima’s tallest waterfall with year-round flow. A cave beside it was mined for sulfur used in gunpowder around the First Sino-Japanese War (1894–1895).
In Mihara’s wet upper ravines, Hego tree ferns grow at Japan’s northernmost natural limit. The Okawa and Kamogawa headwaters here are protected as a national Natural Monument.
Porous volcanic scoria over water-tight deposits lets Mihara store rain underground, feeding its waterfalls and rivers. Those rivers have irrigated island rice paddies for generations, where fireflies appear in summer.
Aston’s tit, an Izu Islands subspecies of the varied tit, has an unusually small neighborhood on Hachijojima: its known range is confined to the Mihara side.
Sulfur Pond is not simply a natural volcanic pool: Tokyo’s regional record describes it as a man-made reservoir from the Muromachi period. Its sulfur-bearing water can shift from blue-green to turquoise or green with the weather and seasons.
In Sueyoshi forest on Mihara, flowing water spins small stones against the bedrock, gradually grinding potholes more than 1 m across and deep. These striking natural rock bowls are designated Hachijo Town natural monuments.
Mihara’s underground heat once generated electricity for Hachijojima: a geothermal plant on the mountain’s southwest flank opened in 1999 as the first on a Japanese outlying island, producing 3,300 kW before closing in 2019.
