Izu Oshima: To the Crater of Mt. Mihara, Ura-sabaku Desert, Habu Port, and the Great Strata Cross-Section

This route circles the crater of Izu Oshima's Mt. Mihara on a crater rim walk, then drives clockwise along the Oshima Circular Route to explore the Ura-sabaku Desert, Habu Port, and the Great Strata Cross-Section.

History and Regional Appeal

The entire island of Izu Oshima is an active volcano. Historically, the island's residents revered its volcanic eruptions as "Gojinka" (sacred fire). Mt. Mihara, located within the caldera at the summit, took its present form during the major An'ei eruption between 1777 and 1778. Because southwesterly winds frequently blow across the island, thick layers of volcanic ejecta accumulated to the northeast of the crater with each eruption. In the Ura-sabaku Desert, which extends across the northeastern flank of Mt. Mihara, strong winds have made it difficult for vegetation to take root, preserving this black desert landscape over many years. Habu Port in the southeast was originally formed as a crater lake by an eruption believed to have occurred in the early 9th century; it was subsequently connected to the ocean by the massive tsunami of the 1703 Genroku earthquake and developed into a port by human hands. On the southwestern part of the island, the Great Strata Cross-Section displays striped layers of ejecta from over 100 major eruptions repeated over the past approximately 18,000 years. In a single day, visitors can trace the marks left by volcanic eruptions in four distinct forms: a crater, a desert, a port, and geological strata.

Key Highlights

• ​Mt. Mihara​​: An "Ohachi-meguri" (crater rim walk) course is established along the crater rim, allowing visitors to see up close the pit-like crater measuring 300 to 350 meters in diameter and about 200 meters deep. The black streaks on the slopes are traces of lava flows from the 1950–1951 and 1986 eruptions. At Mihara Shrine on the summit, visitors can view Mt. Fuji framed through the torii gate if weather conditions are favorable.
• ​Ura-sabaku Desert​​: A vast black terrain covered in volcanic ash and scoria that stretches across the entire northeastern side of Mt. Mihara. With no man-made structures in sight, the blue ocean expands beyond the dark ground, and one can hear the crunching sound of scoria beneath their feet with every step.
• ​Habu Port​​: A port town that flourished as a harbor for waiting out winds, sheltered by a natural windbreak. It is associated with the song "Habu no Minato" and Kawabata Yasunari's The Dancing Girl of Izu. Preserved historic buildings include the three-story wooden Former Minatoya Ryokan and the Former Jinnomaru Residence with its traditional namako walls.
• ​Great Strata Cross-Section​​: A geological cross-section measuring about 24 meters high and 630 meters long, exposed when the mountainside was excavated during road construction in 1953. Because of its appearance, it is affectionately called the "Baumkuchen."

Suggested Itinerary and Travel Time

Access to the island from Takeshiba Pier takes as little as 1 hour and 45 minutes by high-speed jetfoil, or at least 6 hours by large overnight passenger ship. The island has two ports: Motomachi Port and Okada Port. Motomachi Port is the main harbor, but ships dock at Okada Port when westerly winds blow. The designated port of arrival for the day is announced on the official Tokai Kisen website. Traveling around the island is done by car, with a recommended duration of about one full day. First, drive a rental car to the Mt. Mihara Summit Entrance (Mihara Sancho-guchi). After viewing the caldera from the nearby Gairinzan Observation Deck, hike up toward the crater for the crater rim walk. It takes approximately 2 hours and 45 minutes to complete the walk and return to the summit entrance. Since there is almost no shade along the trail, be sure to carry a hat and drinks. Next, drive clockwise along the Oshima Circular Route to the eastern side of the island. The Ura-sabaku Desert is about a 40-minute drive clockwise from Motomachi Port. Turn onto a narrow road marked by a small sign reading "Tsuki to Sabaku Line Entrance" off the circular route, and walk about 800 meters from the parking area at the end of the road. After the Ura-sabaku Desert, proceed south along the circular route to Habu Port. Stop at the Habu Port Observation Deck by the roadside to look over the distinctive shape of the harbor that was once a crater lake, then head down to the port. Ascending the Odoriko Slope in front of the Former Minatoya Ryokan leads to the Former Jinnomaru Residence. Finally, follow the same road about 6 kilometers west-northwest from Habu Port to the Great Strata Cross-Section. In autumn and winter, visitors may sometimes see the strata illuminated by the setting sun. From the Great Strata Cross-Section back to Motomachi Port takes about 15 minutes by car.

Experience Summary

Stand on the edge of the crater to gaze into the deep pit, listen to the crunch of scoria in the black desert, stroll the alleys of a port that began as a crater lake, and stand before the striped layers of past eruptions. Spend a day exploring the varied landscapes shaped by volcanic activity across the active volcanic island of Izu Oshima.