The Northeastern Japan Arc, also Northeastern Honshū Arc, is an
island arc
Island arcs are long archipelago, chains of active volcanoes with intense earthquake, seismic activity found along convergent boundary, convergent plate tectonics, tectonic plate boundaries. Most island arcs originate on oceanic crust and have re ...
on the
Pacific Ring of Fire. The arc runs north to south along 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 result of the
subduction of the
Pacific plate underneath the
Okhotsk plate at the
Japan Trench. The southern end of the arc converges with the
Southwestern Japan Arc and the
Izu–Bonin–Mariana Arc at the Fossa Magna (
ja) at the east end of the
Itoigawa-Shizuoka Tectonic Line (ITIL). This is the geologic border between eastern and western Honshū.
Mount Fuji
is an active stratovolcano located on the Japanese island of Honshu, with a summit elevation of . It is the highest mountain in Japan, the second-highest volcano on any Asian island (after Mount Kerinci on the Indonesian island of Sumatra), a ...
is at the point where these three arcs meet. To the north, the Northeastern Japan arc extends through the
Oshima Peninsula of
Hokkaidō. The arc converges in a collision zone with the
Sakhalin Island Arc and the
Kuril Island Arc in the volcanic
Ishikari Mountains of central Hokkaidō. This collision formed the
Teshio and
Yūbari Mountains.
The
Ōu Mountains
The are a mountain range in the Tōhoku region of Honshū, Japan. It is the longest range in Japan and stretches south from the Natsudomari Peninsula of Aomori Prefecture to the Nasu volcanoes at the northern boundary of the Kantō region. T ...
form the backbone of the volcanic part of the
inner arc that run from
Natsudomari Peninsula in
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 ...
south to
Mount Nikkō-Shirane in
Tochigi and
Gunma prefectures. The
volcanic front consists of four north to south lines 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 and calderas, which extend the length of the range. It also includes the Quaternary volcanoes of southwestern Hokkaido. The
Dewa Mountains and the
Iide Mountains 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
The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...
and have since been worn smooth by erosion.
References
Geology of Japan
Plate tectonics
Volcanic arcs
{{East Asia plates