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The is a 25.810 km terrestrial railway tunnel in Japan — part of the Tōhoku Shinkansen, linking Tokyo with Aomori. When opened in 2002 it was the longest in-use terrestrial (land based) tunnel in world, but the title was overtaken by the Lötschberg Base Tunnel in June 2007. The tunnel is located 545 km away from Tokyo Station on the Tōhoku Shinkansen line, midway between Morioka and Hachinohe.〔 Surveying commenced in 1988. In 1991 construction began, and the tunnel holed through in 2000. The tunnel became operational when the railway line opened in 2002. Maximum depth is about 200 m. ==Geography and geology== The tunnel passes through hilly terrain near the Kitakami and Ou mountains. The Mabuchi and Kitakami rivers run near the tunnel's Tokyo portal.〔 Geology along the tunnel route can be divided into three sections: *17 km from the Tokyo end: Mesozoic and Paleozoic strata (argillite, granodiorite, hornfels and chert) *5 km central section: Neogene volcanic tuff, which was susceptible to swelling and caused engineering difficulties. *4 km from the Aomori end: a combination of the previous two sections, as well as mudstone and andesite of the Neogene period. Faults cross the path of the tunnel.〔 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「Iwate-Ichinohe Tunnel」の詳細全文を読む スポンサード リンク
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