Located 77 km south-southeast from Mikura-jima and 64 km north from Aoga-shima, the island of Hachijō-jima (八丈島) is the southernmost and most isolated of the Izu Shichito (Izu Seven Islands) group — a grouping that comprises the seven northern islands of the Izu-shotō.

Hachijō-jima (62.5 km²) measures 14.5 km in length, orientated in the northwest to southeast direction, with a maximum width of 8 km. The island is formed primarily from two volcanoes: the basaltic Nishi-yama (Mt Hachijō-fuji) stratovolcano on the northwest and the complex andesitic-basaltic Higashi-yama (Mihara-yama) on the southeast.

Rising to a height of 854 m above sea level, the symmetrical cone of Nishi-yama is the tallest peak of the entire Izu-shotō island chain. The summit is occupied by the Oana Crater; at 400 m in diameter the crater is shallow with typical depths of around 50 m. The northwestern side of Oana contains a pit crater known as Koana; measuring 180 m across it reaches a depth of 95 m. The older and broader Higashi-yama volcano on the southeastern section of the island has eroded flanks and reaches a maximum elevation of 701 m above sea level. Historical records have noted volcanic activity on Hachijō-jima to have been confined to the summit crater of Nishi-yama.

Lying around 4 km off the northwestern side of Hachijō-jima is the small island of Kō-jima (3 km²). Orientated in the same northwest to southeast direction as its larger neighbour, the 1.3 x 3 km Kō-jima is a steep-sided island rising to a height of 617 m above sea level.

Synonyms: Hachijō-jima, Hachijojima, Hachijō Island, Hachijojima Island

image: ASTER volcano archive jpl/nasa

©2011 oceandots.com