Kojima

Ko Island (小島, Ko-jima) or Kojima is an uninhabited volcanic island in the Sea of Japan, 23 kilometres (14 mi) southwest of the mainland portion of the town of Matsumae and is the southernmost point in Hokkaidō. It is under the administration of the district of Matsumae in Oshima Subprefecture in Hokkaido, Japan. To distinguish Ko Island from other islands with the same name, it is sometimes known as Oshima Ko Island (渡島小島, Oshima-Kojima) or Matsumae Ko Island (松前小島, Matsumae-Kojima). Ko Island is the world's smallest volcanic island. It has an area of 1.54 square kilometres (0.59 sq mi). The island is an andesitic stratovolcano. The peak consists of non-alkali mafic rocks, dating from the Early Pleistocene overtop of non-alkali felsic rocks from the Late Miocene-Pliocene. Several smaller islets surround Ko Island, including Daihiyakushima, Shohiyakushima, Tenjinshima, and Sazaeshima. To provide refuge for fishing vessels, a small harbor has been put in place.

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