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Fuji-Hakone-Izu NP, Tokyo
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From 1931, sightseers crossed Mt. Mihara’s desert on camels: 2 camels and 11 donkeys were introduced for tourism. By about 1960, horses had replaced the camels; a 1939 archive photo preserves the unusual ride.
Urasabaku is Japan’s only area marked “desert” on Geospatial Information Authority maps. Yet no Sahara-like dunes lie here: Mt. Mihara’s northeast flank is covered in volcanic ash and scoria.
In 2024, a ranger spotted a kawara tiger beetle in neighboring Okuyama-sabaku; Japan’s 2020 Red List classifies it as Endangered. Oshima’s beetles are darker than Tottori’s, and research found their coloring helps them blend with local sand and evade birds.
Before 1986, Urasabaku was covered by finer, sand-like volcanic material. That eruption laid down 20–60 cm of scoria, so much of the dark, crunchy surface visitors see comes from a single eruption.
Urasabaku had a counterpart: Omote-sabaku lay on the caldera’s northwest side. Lava from the 1950–51 eruptions buried most of it, erasing that desert landscape and leaving Urasabaku as the survivor.
Oshima’s daily maximum wind speed reaches at least 10 m/s on about one-third of days. Prevailing southwesterlies drive eruption ash northeast, while wind and rain keep the loose ground shifting and seedlings from taking hold.
Crater gases that once hindered plant growth stopped in the early 1990s. Now hardy Hachijo knotweed is colonizing bare ground here—the start of a gradual shift toward grassland and, eventually, forest elsewhere in the caldera.
A fire on May 5, 2024, burned neighboring Okuyama-sabaku—not Urasabaku proper. On patrol 3 weeks later, an Environment Ministry ranger found new Hachijo-susuki and Hachijo-knotweed shoots already pushing through the burn.
