Izu Islands

The Izu Islands are a volcanic archipelago located in Japan.

They stretch south and east from the Izu Peninsula on the island of Honshu.

Although many people refer to them as the "Seven Islands of Izu," the group actually contains more than a dozen islands and islets. Most of these islands are protected within the Fuji-Hakone-Izu National Park. Administratively, the islands belong to Tokyo Prefecture. They are organized into two towns and six villages. The islands are quite diverse in size and population. Izu Ōshima is the largest island, housing 8,346 inhabitants. In contrast, Toshima is the smallest inhabited island with only 292 people.

The islands formed through intense geological processes. They are part of the Izu–Bonin–Mariana Arc. This arc is a chain of volcanic features that extends to Mount Fuji on the mainland. The islands are oceanic islands. This means they formed in the ocean and were never connected to the Japanese mainland. They appeared relatively recently, within the last few million years. Because they are near the mainland, they serve as a unique laboratory for scientists. Many species have traveled from the mainland to colonize the islands. For example, the Bellflower plant arrived during a single event. The Euhadra snails also arrived in one single event. However, Apodemus mice arrived from the mainland during two separate events.

Volcanic activity is a defining characteristic of this region. The islands sit near a tectonic triple junction. This location causes frequent volcanic eruptions and seismic activity. These events can be dangerous for the people living there. In 1953, an eruption at Myōjin-shō destroyed the research vessel Kaiyō Maru no 5. This event resulted in 31 deaths. In the year 2000, volcanic activity and harmful gases forced the evacuation of Miyakejima. Residents were not able to return permanently until February 2005. Even after returning, residents must carry gas masks for safety. To manage these risks, the Tokyo metropolitan government uses hazard maps and evacuation guidance. They also maintain special radios and transport systems for emergency supplies.

Human history on the islands has changed significantly over time. During the Edo period, certain islands served as places of exile. Criminals were sent to Nii-jima, Miyake-jima, and Hachijō-jima. In 1643, the Dutch explorer Maarten Gerritsz Vries described the islands to Europe. He named them the De Vries Archipelago. The political status of the islands shifted through several administrative changes. In 1871, they were part of Ashigara Prefecture. By 1876, they moved to Shizuoka Prefecture. Finally, in 1878, they came under the jurisdiction of Tokyo Prefecture. This administrative structure remains in place today.

The population of the Izu Islands has seen some changes. In 1960, the total population was 38,707 people. By 2005, the population had dropped to 26,242 people. While this is a decrease, the pace is not as dramatic as other isolated Japanese islands. The islands support a variety of industries to sustain their residents. Fisheries and agriculture are primary sources of income. Tourism is also a major industry for the local economy. Many people visit the islands during the summer months. Popular activities include scuba diving, surfing, and trekking.

Traveling between the islands and the mainland requires specific infrastructure. There are five airports and 15 harbors available. There are also 19 fishing ports to support the local maritime industry.

Travelers can reach the islands from Tokyo in several ways. A flight takes only about 30 minutes. Jetfoils can complete the trip in approximately two hours. Cargo-passenger boats are another option, though they take 7 to 10 hours. On the islands themselves, paved main roads help maintain the quality of life. Modern amenities have also arrived over time. There was no electricity on the islands before 1953. However, by 1962, 98% of the area had access to electricity.

Today, the Izu Islands remain a vital part of the Japanese archipelago. They connect the mainland to the more distant Ogasawara Islands. The Ogasawara Islands are also part of Tokyo but lie much further south. Some islands, like Torishima, are now uninhabited. Torishima serves as an important refuge for birds. Other small locations, such as Smith Island and Lot's Wife, are not part of any municipality. These areas are controlled directly by the Hachijō Subprefecture. Whether through their unique biology or their active volcanoes, the islands continue to be a place of great interest.