Izu Islands

)[citation needed] Of the inhabited islands, seven are traditionally referred to as the "Izu Seven": Oshima, Toshima, Niijima, Kozushima, Miyakejima, Hachijojima, and Mikurajima, though Shikinejima and Aogashima are sometimes included as well.

[citation needed] During the Edo period, Nii-jima, Miyake-jima, and Hachijō-jima served as places of exile for criminals.

They form a far-flung archipelago of over thirty (30) islands some 1,000 km (621 mi) due south of Tokyo.

[citation needed] The four southernmost islands are not administered under any town or village in Hachijō Subprefecture, but are unincorporated areas.

Popular tourist activities include swimming, scuba diving, surfing, fishing, bird watching and trekking.

Transportation on the islands is considered important to the quality of life, which is why about 215 km (134 mi) of paved main roads have been constructed to serve various kinds of vehicles.

Residents were allowed to return permanently to the island in February 2005 but were required to carry gas masks in case of future volcanic emissions.

[citation needed] To handle the various types of natural disasters threatening the region, including tsunamis, storm, floods, and volcanism, Tokyo metropolitan government has developed prevention and safety measures, including hazard maps and evacuation guidance, radios, signs, and a transport system for emergency supplies.