Okinawa Plate

The Okinawa Plate, or Okinawa Platelet, is a minor continental tectonic plate in the northern and eastern hemispheres stretching from the northern end of Taiwan to the southern tip of the island of Kyūshū.[1][2] The Okinawa Plate hosts typical earthquakes, like the 1911 Kikai Island earthquake, and various types of slow earthquakes, including low frequency earthquakes,[3] very low frequency earthquakes,[4] tremor,[5] and slow slip events.[6]

Okinawa Plate
The Okinawa Plate
TypeMinor
Movement1south-east
Speed154mm/year
FeaturesOkinawa, Taiwan
1Relative to the African Plate

Boundaries

The eastern side of the Okinawa Plate forms a convergent boundary with the Philippine Sea Plate, forming the Ryukyu Trench and the island arc that forms the Ryukyu Islands. The Okinawa Plate is bounded on the western side by the Okinawa Trough, a back arc basin and divergent boundary with the Yangtze Plate. A section of the southern boundary between the Okinawa Plate and the Philippine Sea Plate is a former subduction zone that now accommodates oblique slip and was the location of the 1771 Great Yaeyama Tsunami.[7][8] The northern side of the Okinawa plate is bordered by the Amur Plate.

References

  1. ^ Sibuet, Jean-Claude; Letouzey, Jean; Barbier, Florence; Charvet, Jacques; Foucher, Jean-Paul; Hilde, Thomas W. C.; Kimura, Masaaki; Chiao, Ling-Yun; Marsset, Bruno (1987). "Back Arc Extension in the Okinawa Trough". Journal of Geophysical Research: Solid Earth. 92 (B13): 14041–14063. doi:10.1029/JB092iB13p14041. ISSN 2156-2202.
  2. ^ Lin, Jing-Yi; Sibuet, Jean-Claude; Lee, Chao-Shing; Hsu, Shu-Kun; Klingelhoefer, Frauke; Auffret, Yves; Pelleau, Pascal; Crozon, Jacques; Lin, Cheng-Horng (2009). "Microseismicity and faulting in the southwestern Okinawa Trough". Tectonophysics. 466 (3–4): 268–280. doi:10.1016/j.tecto.2007.11.030. ISSN 0040-1951.
  3. ^ Katsumata, Akio; Kamaya, Noriko (2003). "Low-frequency continuous tremor around the Moho discontinuity away from volcanoes in the southwest Japan". Geophysical Research Letters. 30 (1): 20–1-20-4. doi:10.1029/2002gl015981. ISSN 0094-8276.
  4. ^ Nakamura, Mamoru; Sunagawa, Naoya (2015-02-24). "Activation of very low frequency earthquakes by slow slip events in the Ryukyu Trench". Geophysical Research Letters. 42 (4): 1076–1082. doi:10.1002/2014gl062929. ISSN 0094-8276.
  5. ^ Yamashita, Y.; Yakiwara, H.; Asano, Y.; Shimizu, H.; Uchida, K.; Hirano, S.; Umakoshi, K.; Miyamachi, H.; Nakamoto, M. (2015-05-07). "Migrating tremor off southern Kyushu as evidence for slow slip of a shallow subduction interface". Science. 348 (6235): 676–679. doi:10.1126/science.aaa4242. ISSN 0036-8075.
  6. ^ Nishimura, Takuya (2014-10-11). "Short-term slow slip events along the Ryukyu Trench, southwestern Japan, observed by continuous GNSS". Progress in Earth and Planetary Science. 1 (1). doi:10.1186/s40645-014-0022-5. ISSN 2197-4284.
  7. ^ Bird, Peter (2003). "An updated digital model of plate boundaries: UPDATED MODEL OF PLATE BOUNDARIES". Geochemistry, Geophysics, Geosystems. 4 (3). doi:10.1029/2001GC000252.
  8. ^ Okamura, Yukinobu; Nishizawa, Azusa; Fujii, Yushiro; Yanagisawa, Hideaki (2018-09-11). "Accretionary prism collapse: a new hypothesis on the source of the 1771 giant tsunami in the Ryukyu Arc, SW Japan". Scientific Reports. 8 (1). doi:10.1038/s41598-018-31956-8. ISSN 2045-2322. PMC 6134009.
Amurian Plate

The Amurian Plate (or Amur Plate; also occasionally referred to as the China Plate) is a minor tectonic plate in the northern and eastern hemispheres. It covers Manchuria, the Korean Peninsula, the Yellow Sea, and Primorsky Krai. Once thought to be a part of the Eurasian Plate, the Amur Plate is now generally considered to be a separate plate moving southeast with respect to the Eurasian Plate.

The Amurian Plate is named after the Amur River, that forms the border between the Russian Far East and Northeastern China.

It is bounded on the north, west, and southwest by the Eurasian Plate, on the east by the Okhotsk Plate, to the southeast by the Philippine Sea Plate along the Suruga Trough and the Nankai Trough, and the Okinawa Plate, and the Yangtze Plate.The Baikal Rift Zone is considered a boundary between the Amurian Plate and the Eurasian Plate. GPS measurements indicate that the plate is slowly rotating counterclockwise.

The Amurian Plate may have been involved in the 1976 Tangshan earthquake in China.

Geography of Japan

Japan is an island country comprising a stratovolcanic archipelago over 3,000 km (1,900 mi) along East Asia's Pacific coast. It consists of 6,852 islands. The 5 main islands are Hokkaido, Honshu, Kyushu, Shikoku and Okinawa. There are 6,847 'remote islands'. The Ryukyu Islands and Nanpō Islands are south and east of the main islands.

The territory extends 377,973.89 km2 (145,936.53 sq mi). It is the 4th largest island country in the world and the largest island country in East Asia. Japan has the sixth longest coastline 29,751 km (18,486 mi) and the eighth largest Exclusive Economic Zone of 4,470,000 km2 (1,730,000 sq mi) in the world.The terrain is mostly rugged and mountainous with 66% forest. The population is clustered in urban areas on the coast, plains and valleys. Japan is located in the northwestern Ring of Fire on multiple tectonic plates. East of the Japanese archipelago are three oceanic trenches. The Japan Trench is created as the oceanic Pacific Plate subducts beneath the continental Okhotsk Plate. The continuous subduction process causes frequent earthquakes, tsunami and stratovolcanoes. The islands are also affected by typhoons. The subduction plates have pulled the Japanese archipelago eastward, created the Sea of Japan and separated it from the Asian continent by back-arc spreading 15 million years ago.The climate of the Japanese archipelago varies from humid continental in the north (Hokkaido) to humid subtropical and tropical rainforest in the south (Okinawa Prefecture). These differences in climate and landscape have allowed the development of a diverse flora and fauna, with some rare endemic species, especially in the Ogasawara Islands.

Japan extends from 20° to 45° north latitude (Okinotorishima to Benten-jima) and from 122° to 153° east longitude (Yonaguni to Minami Torishima). Japan is surrounded by seas. To the north the Sea of Okhotsk separates it from the Russian Far East, to the west the Sea of Japan separates it from the Korean Peninsula, to the southwest the East China Sea separates the Ryukyu Islands from China and Taiwan, to the east is the Pacific Ocean.

Geology of Japan

The islands of Japan are primarily the result of several large ocean movements occurring over hundreds of millions of years from the mid-Silurian to the Pleistocene as a result of the subduction of the Philippine Sea Plate beneath the continental Amurian Plate and Okinawa Plate to the south, and subduction of the Pacific Plate under the Okhotsk Plate to the north.

Japan was originally attached to the eastern coast of the Eurasian continent. The subducting plates, being deeper than the Eurasian plate, pulled Japan eastward, opening the Sea of Japan around 15 million years ago. The Strait of Tartary and the Korea Strait opened much later.

Japan is situated 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. Hot springs are numerous and have been developed as resorts.

Geology of Taiwan

The island of Taiwan is active geologically, formed on a complex convergent boundary between the Yangtze Subplate of the Eurasian Plate to the west and north, the Okinawa Plate on the north-east, the Philippine Plate on the east and south, and the Sunda Plate to the southwest. Subduction changes direction at Taiwan.

The upper part of the crust on the island is primarily made up of a series of terranes, mostly old island arcs which have been forced together by the collision of the forerunners of the Eurasian Plate and the Philippine Sea Plate, which is moving to the northeast. These have been further uplifted as a result of the detachment of a portion of the Eurasian Plate as it was subducted beneath remnants of the Philippine Sea Plate, a process which left the crust under Taiwan more buoyant.South of Taiwan, the Philippine Sea Plate is subducting under the Sunda Plate, forming the Luzon Volcanic Arc (including Green Island and Orchid Island). The east and south of the island are a complex system of belts formed by, and part of the zone of, active collision between the North Luzon Trough portion of the Luzon Volcanic Arc and the Eurasian Plate, where accreted portions of the Luzon Arc and Luzon forearc form the eastern Coastal Range and parallel inland Taitung Longitudinal Valley of Taiwan respectively.To the northeast, the Philippine Sea Plate is subducting under the Okinawa Plate, forming the Ryukyu Volcanic Arc.

Geology of the Pacific Ocean

The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific Plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth.The tectonic plates continue to move today. The slowest spreading ridge is the Gakkel Ridge on the Arctic Ocean floor, which spreads at less than 2.5 cm/year (1 in/year), while the fastest, the East Pacific Rise near Easter Island, has a spreading rate of over 15 cm/year (6 in/year).

Japan

Japan (Japanese: 日本, Nippon [ɲippoꜜɴ] (listen) or Nihon [ɲihoꜜɴ] (listen); formally 日本国, Nippon-koku or Nihon-koku, lit. 'State of Japan') is an island country in East Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asian continent and stretches from the Sea of Okhotsk in the north to the East China Sea and the Philippine Sea in the south.

The kanji that make up Japan's name mean 'sun origin', and it is often called the "Land of the Rising Sun". Japan is the world's 4th largest island country and encompasses about 6,852 islands. The stratovolcanic archipelago has five main islands: Honshu, Hokkaido, Kyushu, Shikoku and Okinawa which make up about 97% percent of Japan's land area. The country is divided into 47 prefectures in eight regions, with Hokkaido being the northernmost prefecture and Okinawa being the southernmost one (albeit, in Japanese culture the country is considered to be divided east to west ). Japan is the 2nd most populous island country. The population of approximately 126 million is the world's eleventh largest, of which 98.5% are ethnic Japanese. 90.7% of people live in cities, while 9.3% live in the countryside. About 13.8 million people live in Tokyo, the capital of Japan. The Greater Tokyo Area is the most populous metropolitan area in the world with over 38 million people.Archaeological research indicates that Japan was inhabited as early as the Upper Paleolithic period. The first written mention of Japan is in Chinese history texts from the 1st century AD. Influence from other regions, mainly China, followed by periods of isolation, particularly from Western Europe, has characterized Japan's history.

From the 12th century until 1868, Japan was ruled in the name of the Emperor by successive feudal military shōguns. Japan entered into a long period of isolation in the early 17th century, which was ended in 1853 when a United States fleet pressured Japan to open to the West. After nearly two decades of internal conflict and insurrection, the Imperial Court regained its political power in 1868 through the help of several clans from Chōshū and Satsuma – and the Empire of Japan was established. In the late 19th and early 20th centuries, victories in the First Sino-Japanese War, the Russo-Japanese War and World War I allowed Japan to expand its empire during a period of increasing militarism. The Second Sino-Japanese War of 1937 expanded into part of World War II in 1941, which came to an end in 1945 following the Japanese surrender. Since adopting its revised constitution on May 3, 1947, during the occupation led by SCAP, the sovereign state of Japan has maintained a unitary parliamentary constitutional monarchy with an Emperor and an elected legislature called the National Diet.

Japan is a member of the ASEAN Plus mechanism, UN, the OECD, the G7, the G8, and the G20, and is considered a great power. Its economy is the world's third-largest by nominal GDP and the fourth-largest by purchasing power parity. It is also the world's fourth-largest exporter and fourth-largest importer.

Japan benefits from a highly skilled and educated workforce; it has among the world's largest proportion of citizens holding a tertiary education degree. Although it has officially renounced its right to declare war, Japan maintains a modern military with the world's eighth-largest military budget, used for self-defense and peacekeeping roles; it ranked as the world's fourth-most powerful military in 2015. Japan is a highly developed country with a very high standard of living and Human Development Index. Its population enjoys one of the highest life expectancy and the third lowest infant mortality rate in the world, but is experiencing issues due to an aging population and low birthrate. As of 2019, Japanese citizens had visa-free or visa-on-arrival access to 189 countries and territories, ranking the Japanese passport 1st in the world, tied with Singapore. Japan is renowned for its striking art, historical and extensive cinema, influential music industry, manga, anime, video gaming, rich cuisine and its major contributions to science and modern technology.

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 magnitude scale (Mw), or the surface wave magnitude scale (Ms) for very old earthquakes. The present list is not exhaustive, and reliable and precise magnitude data is scarce for earthquakes that occurred prior to the development of modern measuring instruments.

List of tectonic plates

This is a list of tectonic plates on the Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks.

Mining in Japan

Mining in Japan is minimal because Japan does not possess many on-shore mineral resources. Many of the on-shore minerals have already been mined to the point that it has become less expensive to import minerals. There are small deposits of coal, oil, iron and minerals in the Japanese archipelago. Japan is scarce in critical natural resources and has been heavily dependent on imported energy and raw materials. There are major deep sea mineral resources in the seabed of Japan. This is not mined yet due to technological obstacles for deep sea mining.

Nankai megathrust earthquakes

Nankai megathrust earthquakes are great megathrust earthquakes that occur along the Nankai megathrust – the fault under the Nankai Trough – which forms the plate interface between the subducting Philippine Sea Plate and the overriding Amurian Plate (part of the Eurasian Plate), which dips beneath southwestern Honshu, Japan. The fault is divided into five segments in three zones, which rupture separately or in combination, and depending on location, the resulting earthquakes are subdivided by zone from west to east into Nankai earthquakes, Tōnankai earthquakes, and Tōkai earthquakes.

The earthquakes occur with a return period of about 90–200 years, and often occur in pairs, where a rupture along part of the fault is followed by a rupture elsewhere, notably the 1854 Ansei-Tōkai earthquake and the 1854 Ansei-Nankai earthquake the next day, and the 1944 Tōnankai earthquake, followed by the 1946 Nankaidō earthquake. In one recorded case (the 1707 Hōei earthquake) the fault ruptured along its entire length. All of these great earthquakes have resulted in damaging tsunamis, which are particularly damaging due to the Japanese population being concentrated on the Taiheiyō Belt, especially the coastal cities of Tokyo and Osaka, the two most populous in Japan. The area remains seismically active, and future earthquakes are anticipated, with a high risk of a Nankai earthquake in the near future, which could be potentially very damaging.

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 the Philippine Mobile Belt, which is geologically and tectonically separate from the Philippine Sea Plate.

Philippine Sea plate is bordered mostly by convergent boundaries:

To the north, the Philippine Sea Plate meets the Okhotsk Plate at the Nankai Trough. The Philippine Sea Plate, the Amurian Plate, and the Okhotsk Plate meet at Mount Fuji in Japan. The thickened crust of the Izu-Bonin-Mariana arc colliding with Japan constitutes the Izu Collision Zone.

To the east, Philippine Sea Plate meets the Pacific Plate, subducting at the Izu-Ogasawara Trench. The east of the plate includes the Izu-Ogasawara (Bonin) and the Mariana Islands, forming the Izu-Bonin-Mariana Arc system. There is also a divergent boundary between the Philippine Sea Plate and the small Mariana Plate which carries the Mariana Islands.

To the south, the Philippine Sea Plate is bounded by the Caroline Plate and Bird's Head Plate.

To the west, the Philippine Sea Plate subducts under the Philippine Mobile Belt at the Philippine Trench and the East Luzon Trench. (The adjacent rendition of Prof. Peter Bird's map is inaccurate in this respect.)

To the northwest, the Philippine Sea Plate meets Taiwan and the Nansei islands on the Okinawa Plate, and southern Japan on the Amurian Plate.

Taiwan

Taiwan, officially the Republic of China (ROC), is a state in East Asia. Neighbouring states include the People's Republic of China (PRC) (China mainland) to the west, Japan to the north-east, and the Philippines to the south. The island of Taiwan has an area of 35,808 square kilometres (13,826 sq mi), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanised population is concentrated. Taipei is the capital and largest metropolitan area. Other major cities include Kaohsiung, Taichung, Tainan and Taoyuan. With 23.7 million inhabitants, Taiwan is among the most densely populated states, and is the most populous state and largest economy that is not a member of the United Nations (UN).

Taiwanese indigenous peoples settled the island of Taiwan around 6,000 years ago. In the 17th century, Dutch rule opened the island to mass Han immigration. After a brief rule by the Kingdom of Tungning, the island was annexed in 1683 by the Qing dynasty of China, and ceded to the Empire of Japan in 1895. Following the surrender of Japan in 1945, the Republic of China, which had overthrown and succeeded the Qing in 1911, took control of Taiwan on behalf of the World War II Allies. The resumption of the Chinese Civil War led to the loss of the mainland to the Communist Party of China and the flight of the ROC government to Taiwan in 1949. Although the ROC government continued to claim to be the legitimate representative of China, since 1950 its effective jurisdiction has been limited to Taiwan and several small islands. In the early 1960s, Taiwan entered a period of rapid economic growth and industrialisation called the "Taiwan Miracle". In the late 1980s and early 1990s, the ROC transitioned from a one-party military dictatorship to a multi-party democracy with a semi-presidential system.

Taiwan's export-oriented industrial economy is the 21st-largest in the world, with major contributions from steel, machinery, electronics and chemicals manufacturing. Taiwan is a developed country, ranking 15th in GDP per capita. It is ranked highly in terms of political and civil liberties, education, health care and human development.The political status of Taiwan remains uncertain. The ROC is no longer a member of the UN, having been replaced by the PRC in 1971. Taiwan is claimed by the PRC, which refuses diplomatic relations with countries that recognise the ROC. Taiwan maintains official ties with 14 out of 193 UN member states and the Holy See. International organisations in which the PRC participates either refuse to grant membership to Taiwan or allow it to participate only on a non-state basis. Taiwan is a member of the World Trade Organization, Asia-Pacific Economic Cooperation and Asian Development Bank under various names. Nearby countries and countries with large economies maintain unofficial ties with Taiwan through representative offices and institutions that function as de facto embassies and consulates. Domestically, the major political division is between parties favouring eventual Chinese unification and promoting a Chinese identity contrasted with those aspiring to independence and promoting Taiwanese identity, although both sides have moderated their positions to broaden their appeal.

Yangtze Plate

The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the south by the Sunda Plate and the Philippine Sea Plate, and on the north and west by the Eurasian Plate. The Longmenshan Fault on the latter border was the site of the 2008 Wenchuan earthquake.The Yangtze Plate was formed by the disaggregation of the Rodinia Supercontinent 750 million years ago, in the Neoproterozoic era. South China rifted away from the Gondwana supercontinent in the Silurian. During the formation of the great supercontinent Pangaea, South China was a smaller, separate continent located off the east coast of the supercontinent and drifting northward. In the Triassic the Yangtze Plate collided with the North China Plate, thereby connecting with Pangaea, and formed the Sichuan basin. In the Cenozoic the Yangtze Plate was influenced by the collision of the Indian and Eurasian plates creating the uplifting of the Longmen Mountains. Its southward motion is accommodated along the Red River fault.

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