The islands of
Japan are primarily the result of several large ocean movements occurring over hundreds of millions of years from the mid-
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago (Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoi ...
to the
Pleistocene
The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...
, as a result of the
subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...
of the
Philippine Sea Plate
The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...
beneath the continental
Amurian Plate and
Okinawa Plate to the south, and subduction of the
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate.
The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and I ...
under the
Okhotsk Plate to the north.
Japan was originally attached to the eastern coast of the
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...
n continent. The subducting plates, being deeper than the Eurasian plate, pulled Japan eastward, opening the
Sea of Japan
The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it h ...
around 15 million years ago. The
Strait of Tartary
Strait of Tartary or Gulf of Tartary (russian: Татарский пролив; ; ja, 間宮海峡, Mamiya kaikyō, Mamiya Strait; ko, 타타르 해협) is a strait in the Pacific Ocean dividing the Russian island of Sakhalin from mainland Asia ...
and the
Korea Strait
The Korea Strait is a sea passage in East Asia between Korea and Japan, connecting the East China Sea, the Yellow Sea and the Sea of Japan in the northwest Pacific Ocean. The strait is split by the Tsushima Island into the Western Channel and ...
opened much later.
Japan is situated in a
volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates ...
zone on the
Pacific Ring of Fire. Frequent low intensity earth tremors and occasional volcanic activity are felt throughout the islands. Destructive
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
s, often resulting in
tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...
s, occur several times per century. The most recent major quakes include the
2011 Tōhoku earthquake and tsunami
The occurred at 14:46 JST (05:46 UTC) on 11 March. The magnitude 9.0–9.1 (M) undersea megathrust earthquake had an epicenter in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region, and lasted approximately six m ...
, the
2004 Chūetsu earthquake and the
Great Hanshin earthquake
The , or Kobe earthquake, occurred on January 17, 1995, at 05:46:53 JST (January 16 at 20:46:53 UTC) in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and h ...
of 1995.
Geological history
Orogeny phase
The breakup of
Rodinia
Rodinia (from the Russian родина, ''rodina'', meaning "motherland, birthplace") was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago and broke up 750–633 million years ago.
were probabl ...
about 750 million years ago formed the
Panthalassa
Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek "all" and "sea"), was the superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During th ...
ocean, with rocks that eventually became Japan sitting on its eastern margin. In the
Early Silurian (450 million years ago), the subduction of the oceanic plates started, and this process continues to the present day, forming a roughly 400 km wide
orogeny
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An '' orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted ...
at the
convergent boundary
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...
. Several (9 or 10) oceanic plates were completely subducted and their remains have formed
paired metamorphic belts. The most recent complete subduction of a plate was that of the
Izanagi Plate 95 million years ago. Currently the Philippine Sea Plate is subducting beneath the continental Amurian Plate and the Okinawa Plate to the south at a speed of 4 cm/year, forming the
Nankai Trough and the
Ryukyu Trench. The Pacific Plate is subducting under the Okhotsk Plate to the north at a speed of 10 cm/year. The early stages of subduction-accretion have recycled the continental crust margin several times, leaving the majority of the modern
Japanese archipelago
The Japanese archipelago ( Japanese: , ''Nihon Rettō'') is an archipelago of 14,125 islands that form the country of Japan. It extends over from the Sea of Okhotsk in the northeast to the East China and Philippine seas in the southwest al ...
composed of rocks formed in the
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Pale ...
period or later.
Island arc phase
Around 23 million years ago, western Japan was a coastal region of the Eurasia continent. The subducting plates, being deeper than the Eurasian plate, pulled parts of Japan which become modern
Chūgoku region
The , also known as the region, is the westernmost region of Honshū, the largest island of Japan. It consists of the prefectures of Hiroshima, Okayama, Shimane, Tottori, and Yamaguchi. In 2010, it had a population of 7,563,428.
History
'' ...
and
Kyushu
is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surroun ...
eastward, opening the Sea of Japan (simultaneously with the
Sea of Okhotsk
The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...
) around 15-20 million years ago, with likely freshwater lake state before the sea has rushed in. Around 16 million years ago, in the
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...
period, a peninsula attached to the eastern coast of the
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...
n continent was well formed. About 11 million years before present, the parts of Japan which become modern
Tōhoku and
Hokkaido
is Japan, Japan's Japanese archipelago, second largest island and comprises the largest and northernmost Prefectures of Japan, prefecture, making up its own List of regions of Japan, region. The Tsugaru Strait separates Hokkaidō from Honshu; th ...
were gradually uplifted from the seafloor, and terranes of
Chūbu region
The , Central region, or is a region in the middle of Honshū, Japan's main island. In a wide, classical definition, it encompasses nine prefectures (''ken''): Aichi, Fukui, Gifu, Ishikawa, Nagano, Niigata, Shizuoka, Toyama, and Y ...
were gradually accreted from the colliding island chains. The Strait of Tartary and the Korea Strait opened much later, about 2 million years ago. At the same time, a severe subduction of
Fossa Magna graben have formed the
Kantō Plain
The is the largest plain in Japan, and is located in the Kantō region of central Honshū. The total area of 17,000 km2 covers more than half of the region extending over Tokyo, Saitama Prefecture, Kanagawa Prefecture, Chiba Prefectur ...
.
Current state
General information
Overall, the geological composition of Japan is poorly understood. The Japanese islands are formed of several geological units parallel to the subduction front. The parts of islands facing oceanic plates are typically younger and display a larger proportion of volcanic products, while the parts facing the Sea of Japan are mostly heavily faulted and folded sedimentary deposits. In north-west Japan, the thick
quaternary deposits make determination of the geological history especially difficult.
Geological structure
The Japanese islands are divided into three major geological domains:
* Northeastern Japan, north of (which had high volcanic activity 14-17 million years before present
)
**
Idosawa Fault
The , also referred to as the Shionihara Fault, is an active earthquake fault system located in Fukushima Prefecture of Japan, to the west of Iwaki city. It mainly consists of a trace of three separate striations.
Structure
The fault was fir ...
**
Senya Fault is a shallow fault system in northern Japan which was responsible for a 7.2 Rikuu earthquake in 1896, along with surface rupture. It is located near the Senya Hills in to the West of the Ou Backbone Range and east of the Yokote Basin in Akita ...
**
Hidaka Mountains
**
**
Ōu Mountains
The are a mountain range in the Tōhoku region of Honshū, Japan. The range 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 r ...
* Central Japan, between Tanakura fault and
Itoigawa-Shizuoka Tectonic Line.
**
Fossa Magna graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...
**
Tanna Fault
is a left lateral strike-slip fault which runs along the northeast side of Izu Peninsula south 30 km to Izu Izu may refer to:
Places
*Izu Province, a part of modern-day Shizuoka prefecture in Japan
**Izu, Shizuoka, a city in Shizuoka pref ...
**
Bōsō Hill Range
The is a mountain range on the Bōsō Peninsula of Chiba Prefecture, Japan. The highest point in the Bōsō Mountain Range is at Mount Atago, with an altitude of . The hill range runs from roughly in a line from Mobara or Ōamishirasato to ...
* Southwestern Japan, south of
Itoigawa-Shizuoka Tectonic Line. The Southwestern Japan is further subdivided into several metamorphic belts stretched along
Japan Median Tectonic Line.
The parts of Japan north of
Japan Median Tectonic Line ("Inner Zone") contains many
granitoid fragments dating from
Paleogene
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of ...
to
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
period intruding the older material, while south of the line ("Outer Zone") is mostly
accretionary complex
An accretionary wedge or accretionary prism forms from sediments accreted onto the non- subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the ...
es of
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
period or younger.
**
Urasoko fault Urasoko fault or Urasoko fault system is a seismic fault (system) running for 39 kilometers near Tsuruga, Japan. Combined with the faults of the system, there are an additional 25 km of faults. It is notable in that it runs 250 meters from Unit # ...
**
Fukozu Fault
**
Neodani Fault
**
Nojima Fault
**Hida orogenic belt (
Hida Mountains
The , or , is a Japanese mountain range which stretches through Nagano, Toyama and Gifu prefectures. A small portion of the mountains also reach into Niigata Prefecture. William Gowland coined the phrase "Japanese Alps" during his time in Japan, ...
and
Ryōhaku Mountains The are a mountain range spanning Gifu, Toyama, Ishikawa, Fukui and Shiga prefectures in Japan. It is divided into the Kaetsu Mountains (加越山地 ''Kaetsu Sanchi''), whose major peak is Mount Haku, and the Etsumi Mountains (越美山地 ...
)
**Sangun orogenic belt
**Maizuru orogenic belt
**Tanba-mino orogenic belt
**Ryoke orogenic belt
**Shimanto orogenic belt
A. Taira, H. Okada, J. H. McD. Whitaker & A. J. Smith, The Shimanto Belt of Japan: Cretaceous-lower Miocene active-margin sedimentation
/ref>
**Sambagawa orogenic belt
**Chichibu orogenic belt
**Sambosan orogenic belt
** Beppu–Shimabara graben
Research
The Geology of Japan is handled mostly by , with the following major periodicals:
* - since 1893
* - since 1968
* - since 1998
Geological hazards
Japan is in a volcanic zone on the Pacific Ring of Fire. Frequent low intensity earth tremors and occasional volcanic activity are felt throughout the islands. Destructive earthquakes, often resulting in tsunamis, occur several times a century. The most recent major quakes include the 2011 Tōhoku earthquake and tsunami, the 2004 Chūetsu earthquake and the Great Hanshin earthquake of 1995.
See also
*Geography of Japan
Japan is an archipelagic country comprising a stratovolcanic archipelago over along the Pacific coast of East Asia. It consists of 6,852 islands. The five main islands are Hokkaido, Honshu, Kyushu, Shikoku and Okinawa. There are 6,847 remote i ...
* Seismicity in Japan
*List of earthquakes in Japan
This is a list of earthquakes in Japan with either a magnitude greater than or equal to 7.0 or which caused significant damage or casualties. As indicated below, magnitude is measured on the Richter magnitude scale (''ML'') or the moment magnitud ...
*List of volcanoes in Japan
This is a list of active and extinct volcanoes in Japan. An Orange background indicates a volcano considered active by the Japan Meteorological Agency.
Hokkaido
Honshū
Izu Islands
Ogasawara Archipelago
The Ogasawara Archipela ...
* List of mines in Japan
References
Further reading
*
*
by - (Author),
*
External links
Geological Survey of Japan - English homepage
Geological Journal of Japan - English homepage
* National Archives of Japan
The preserve Japanese government documents and historical records and make them available to the public. Although Japan's reverence for its unique history and art is well documented and illustrated by collections of art and documents, there is a ...
''Tatoroyama no ki,'' survey of limestone cave in Mount Tatoro in Kozuke Province, 1837 (''Tenpo 8'').
{{Asia topic, Geology of