Tokyo's volcanic backyard: the Izu Islands are a living laboratory for evolution and exile.

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: Stretching south from the Izu Peninsula, the Izu Islands are a volcanic chain administratively tethered to Tokyo. While famous for tourism and their unique Hachijō language, these islands have served as historical penal colonies and remain a high-stakes environment where residents once carried gas masks to survive volcanic emissions.

The Izu Islands comprise more than a dozen volcanic islands, though only nine are currently inhabited. Geologically, they form the northern portion of the Izu–Bonin–Mariana Arc, a chain that connects to Mount Fuji on the Honshū mainland. Unlike isolated Pacific archipelagos such as Hawaii, the Izu Islands are close enough to the mainland that they have been frequently colonized by species through overseas dispersal, making them a premier site for studying ecological and evolutionary processes.

The islands' history is as turbulent as their geology. During the Edo period, and dating back to at least the 12th century, the islands were used as places of exile for criminals. Today, they are part of the Tokyo Metropolis, though they face constant natural threats. In 2000, volcanic activity on Miyake-jima forced a total evacuation; residents were only permitted to return permanently in 2005, provided they carried gas masks to mitigate the risk of future toxic emissions. Such hazards have prompted the Tokyo government to implement rigorous safety measures, including specialized hazard maps and emergency transport systems.

Despite their proximity to Tokyo, the islands maintain a distinct identity. They are home to the divergent Hachijō language and have seen unique biological colonization events, such as the Campanula bellflower, which populated the entire archipelago in a single instance. While the population has been in decline, the archipelago remains a vital hub for fisheries, agriculture, and tourism, supported by a network of five airports and various maritime routes that connect these remote volcanic peaks to the bustling capital.

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