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Ushishir ((ロシア語:Ушишир); Japanese 宇志知島; Ushishiru-tō) is an uninhabited volcanic island located in the centre of the Kuril Islands chain in the Sea of Okhotsk in the northwest Pacific Ocean. Its name is derived from the Ainu language for "hot spring". ==Geology== Ushishir consists of two islets connected by a narrow spit of land with an area of 5 km² 〔(【引用サイトリンク】title=International Kuril Island Project（IKIP） )〕 These islets are the tops of a partially submerged volcano. The southern island (Yankicha (ロシア語:o.Янкича )) consists of the summit caldera and has a maximum width of 2.5 kilometers. The caldera has a diameter of 1.6 kilometers, and is breached on the south, forming a sea-water crater bay. The bay has an estimated depth of 30 meters, and there is strong evidence of ongoing underwater volcanic activity, as evidenced by frequent bubbles, altered water chemistry and the presence of bacteria mats. Two small lava domes for small islands in the central lagoon, and numerous fumaroles and hot springs are along the southeast caldera shoreline. The island’s highest point is 401 meters high, and is on the eastern shore. The northern islet (Ryponkicha (ロシア語:o. Рыпонкча )) is the larger of the two, and consists of a portion of the volcano’s flank, with sheer cliffs rising 131 meters from the sea. Ushishir is still active volcano with a major eruption with the last known eruption in 1884. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ushishir」の詳細全文を読む スポンサード リンク
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