ÅŒu Mountains

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Topography image of the Ou Mountains in the prefectures of Miyagi / Yamagata

The mountain and the city of Morioka in Iwate

The Ou Mountains (Japanese奥 羽 山脉, OU sanmyaku ) is a mountain range in Japan in the Tōhoku region on Honshū.

The mountain range is 500 km, the longest in Japan. It begins on the Natsudomari Peninsula to the north in Aomori Prefecture, then runs as the border between Akita and Iwate prefectures and Yamagata and Miyagi, to the Nasu volcanoes in southern Fukushima Prefecture. Despite its length, the mountain range is only 35 km wide. The highest point is Mount Iwate with 2038 m.

Name

The mountains formed the border between the former provinces Ōshū (奥 州) and Ushu (羽 州), was derived from the name of the mountain.

Geology

The mountains began to form in the Pliocene. It is located above the center of the inner arc of the northeast Japan arc. This is the result of the subduction of the Pacific plate under the North American Plate. A chain of volcanoes that formed during the Quaternary, forming the volcanic front.