mountain range
A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...
in the
Tōhoku region
The , Northeast region, , or consists of the northeastern portion of Honshu, the largest island of Japan. This traditional region consists of six prefectures (): Akita, Aomori, Fukushima, Iwate, Miyagi, and Yamagata.
Tōhoku retains ...
of
Honshū
, historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian ...
, Japan. It is the longest range in Japan and stretches south from the Natsudomari Peninsula of
Aomori Prefecture
is a Prefectures of Japan, prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori (city), Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is border ...
to the Nasu volcanoes at the northern boundary of the
Kantō region
The is a geography, geographical region of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures of Japan, prefectures: Chiba Prefecture, Chiba, Gunma Prefe ...
. Though long, the range is only about wide. The highest point in the range is Mount Iwate, .
The range includes several widely known mountains:
Hakkōda Mountains
The are an active volcanic complex in south-central Aomori Prefecture, Japan, in Towada-Hachimantai National Park. Often called or simply , the mountains are collectively listed as one of the 100 Famous Japanese Mountains. Its highest peak, M ...
These mountains previously formed the boundary between historical provinces of Mutsu (陸奥国) and Dewa (出羽国). The ''
kanji
are logographic Chinese characters, adapted from Chinese family of scripts, Chinese script, used in the writing of Japanese language, Japanese. They were made a major part of the Japanese writing system during the time of Old Japanese and are ...
'' for the name of the mountain range was created from one ''kanji'' of the two provinces, 奥 and 羽, respectively.
Geology
The Ōu Mountains began to form in the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Northeastern Japan Arc. This is the result of the Pacific plate subducting under the Okhotsk plate. A chain of
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...
volcanoes along the range forms the volcanic front.