Northeastern Japan Arc also Northeastern Honshū Arc, is an island arc

Island arc

An island arc is a type of archipelago composed of a chain of volcanoes which alignment is arc-shaped, and which are situated parallel and close to a boundary between two converging tectonic plates....

 on the Pacific Ring of Fire

Pacific Ring of Fire

The Pacific Ring of Fire is an area where large numbers of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements...

. The arc runs north to south along the Tohoku region

Tohoku region

The is a geographical area of Japan. The region occupies the northeastern portion of Honshu, the largest island of Japan. The region consists of six prefectures : Akita, Aomori, Fukushima, Iwate, Miyagi and Yamagata....

 of Honshū

Honshu

is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. It is the result of the subduction

Subduction

In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 of the Pacific Plate

Pacific Plate

The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....

 underneath the North American Plate

North American Plate

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 at the Japan Trench

Japan Trench

__notoc__The Japan Trench is an oceanic trench, a part of the Pacific Ring of Fire, in the floor of the northern Pacific Ocean off northeast Japan. It extends from the Kuril Islands to the Bonin Islands and is at its deepest. It is an extension of the Kuril-Kamchatka Trench to the north and the...

. The southern end of the arc converges with the Southwestern Japan Arc and the Izu-Bonin-Mariana Arc

Izu-Bonin-Mariana Arc

The Izu-Bonin-Mariana arc system is an outstanding example of a plate tectonic convergent boundary. IBM extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, Bonin Islands, and Mariana Islands; much more of the IBM arc system is submerged below sealevel...

 at the Fossa Magna at the east end of the Itoigawa-Shizuoka Tectonic Line

Itoigawa-Shizuoka Tectonic Line

, also Ito Shizu Sen is a major fault on Honshu island that runs from the city of Itoigawa, Niigata Prefecture, through Lake Suwa to the city of Shizuoka in Shizuoka Prefecture. It is often confused with Fossa Magna which lies to the east....

 (ITIL). This is the geologic border between eastern and western Honshū. Mount Fuji

Mount Fuji

is the highest mountain in Japan at . An active stratovolcano that last erupted in 1707–08, Mount Fuji lies about south-west of Tokyo, and can be seen from there on a clear day. Mount Fuji's exceptionally symmetrical cone is a well-known symbol of Japan and it is frequently depicted in art and...

 is at the point where these three arcs meet. To the north, the Northeastern Japan arc extends through the Oshima Peninsula

Oshima Peninsula

The Oshima Peninsula is the southernmost part of Hokkaidō, the northernmost of the Japanese islands. Where the peninsula starts is open to interpretation. A more generous interpretation is to draw a line southeast from Ishikari Bay across the Ishikari Plain to Yufutsu...

 of Hokkaidō

Hokkaido

, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...

. The arc converges in a collision zone with the Sakhalin island arc

Sakhalin island arc

Sakhalin island arc is an ancient volcanic arc dating from the Early Miocene. The arc was a result of the Okhotsk Plate subducting beneath the Eurasian plate in the convergence zone. The arc runs from mainland Asia through Sakhalin Island into central Hokkaido and the collision zone around the...

 and the Kuril arc in the volcanic Ishikari Mountains

Ishikari Mountains

The is a range of volcanic mountains in central Hokkaidō, Japan. The mountain range is made up from the Daisetsuzan Volcanic Group and the Tomuraushi Volcanic Group. The volcanoes are part of the Kurile arc of the Pacific ring of fire.-References:...

 of central Hokkaidō. This collision formed the Teshio

Teshio Mountains

Teshio Mountains is a mountain range of Hokkaidō, Japan....

 and Yubari Mountains

Yubari Mountains

is a mountain range of Hokkaidō, Japan.Part of this range is protected by the .-Geology:The Yūbari Mountains continue the north-south line begun by the Teshio Mountains. The mountains are the result of the collision between the Kurile Island Arc and the Northeastern Japan Arc. Three formations make...

.

The Ōu Mountains

Ou Mountains

The are a mountain range in the Tōhoku region of Honshū, Japan. The range is the longest range in Japan and stretch south from the Natsudomari Peninsula of Aomori Prefecture to the Nasu volcanoes at the northern boundary of the Kantō region. Though long, the range is only about wide...

 form the volcanic part of the inner arc. The volcanic front consists of Quaternary

Quaternary

The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...

 volcanoes, which extend the length of the range. It also includes the Quaternary volcanoes of southwestern Hokkaidō. The Dewa Mountains and the Iide Mountains

Iide Mountains

The or is a mountain range that spans over the Fukushima, Niigata and Yamagata prefectures in Japan. Its highest peak is at 2,128m, and the main peak of the range is Mount Iide at 2,105m above sea level...

 are non-volcanic uplift ranges that run parallel to the west of the Ōu Mountains.

The outer arc ranges are the Kitakami and the Abukuma Mountains. These mountains are made from pre-tertiary rock. The mountains rose in the Cenozoic

Cenozoic

The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...

and have since been worn smooth by erosion.