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🌤 | [Weather on the 21st] Autumn is sunny nationwide in the morning Downhill in western Japan in the afternoon Be careful of the temperature difference between morning and daytime

Photo The lowest temperature until 21 am on the 5st (Wednesday)

[Weather on the 21st] Autumn is sunny nationwide in the morning Downhill in western Japan in the afternoon Be careful of the temperature difference between morning and daytime

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The high pressure that covered the Japanese archipelago gradually moves to the east of Japan, but it seems that there will be many sunny places within the high pressure range today.

Today (Wednesday) 21st, it will be sunny nationwide, mainly in the morning, but in western Japan, clouds will spread from the afternoon and it will rain late at night. → Continue reading

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Japanese archipelago

Japanese archipelago(Japanese Archipelago, Japanese Archipelago,Japanese archipelago) IsEurasiaOff the eastern coastEast AsiaLocated in, alsoThe Pacific OceanLocated in the northwestern coastal areaArc archipelagoone of[*2].. There are several theories about the range, but all of them cover almost the entire area.JapanTerritory[2]It has become. The Japanese archipelago is the name of the archipelago and is a concept independent of the state and territory, but in Japan it is also confused as a word meaning Japanese territory. About the Japanese archipelago as Japan's territoryGeography of japanSee.

The archipelago is wide and has a width of about 300km and a length of about 3500km. The area covering 75% of the land area is mountainous areas and foothills, and there is little flat land. MostlyWarm and humid climateBelongs torainy season,typhoon,Also(I.e.Due to the influence of heavy snowfallErosionIs intense[3].

The surroundingsSea of ​​Japan,Sea of ​​Okhotsk,The Pacific Ocean,Philippine SeaSurrounded by. On the Pacific side of the archipelagoKuril-Kamchatka Trench,Japan Trench,Izu/Ogasawara Trench,Nankai TroughThere are deep trenches such as, and the whole is an active area where crustal movements and orogenic activities are active.[4].. In addition, it is said that about 10% of the volcanoes confirmed on the earth are in the Japanese archipelago.[5].

GeologySpecifically,Eurasia plateEast end andNorth American plateLocated at the southwestern tip of. Under these two continental platesPacific plateとPhilippine Sea PlateIt is believed that the subduction of the two oceanic plates in the continent resulted in an arc-shaped archipelago separated from the continent.[*3].

EoceneThe prototype was formed from around (5,600 million years ago-3,400 million years ago),Miocene(2,300 million years ago-530 million years ago)Sea of ​​JapanWas formed and separated from the Eurasian continent.

範 囲

The interpretation of the range of the Japanese archipelago changes depending on whether it is based on topography or cultural regions.[Source required].. In general, there are two ways of thinking and views, narrow and broad.

The range of the Japanese archipelago in the narrow sense isHokkaido(Hokkaido),Honshu(Honshu),Shikoku(Shikoku),KyusyuThe four islands of Kyushu and the islands that accompany them.[*4].

The scope of the Japanese archipelago in a broad sense is the four islands of Hokkaido, Honshu, Shikoku, and Kyushu and the islands associated with them.Kuril Islands,Nansei Islands.

In terms of geological structure, it is an archipelago consisting of Hokkaido, Honshu, Shikoku, and Kyushu, excluding the Kuril Islands and Nansei Islands.Aleutian IslandsIncludingAsia continentIt is a part of the Kasai archipelago that hangs down on the eastern edge.[6][*5].

Sakhalin IslandとTaiwan IslandAdd[7], And the Nansei Islands,Izu Islands,Ogasawara Islands, The Kuril Islands may be added[*6][*7].

Origin and current terrain

The current Japanese archipelago is mainlyAdductと 呼 ば れ るoceanMade ofSedimentIt consists of. Once near Japan was the edge of the Eurasian continent,PaleozoicWas brought from the continentsand,mud AccumulationWas (currentlyHokurikuNorth,GifuHida region,San'inNorthern part etc.). There, far offshoreMarine plateAccumulated oncoral,RadiolariaConsists ofrock(Limestone,chart) Is moving and that isTrenchWhen sneaking in, it was pressed against the plate of the Asian continent while mixing with sediments from the land (addition). Since this addition has continued intermittently to the present, the Japanese archipelago is made of rock that is older on the Sea of ​​Japan side and newer toward the Pacific Ocean side.

While the ocean plate sneaks into the continental plate by such a mechanism, mainlyJurassic - CretaceousThe prototype of the Japanese archipelago was formed by involving the original rock on the edge of the Asian continent 4-5 million years ago and the fragments of old plates that had been carried, using the rock added to the skeleton. At this point Japan is not yet an archipelago, but now South AmericaAndesIt is probable that the situation was like this.

after that,MioceneThis time the Japanese archipelago is torn from the continentCrustal movementAnd lowlands began to form on the continent[*8].. 2100 million-1100 million years ago, the rupture was even bigger,Southwest Japan TheNagasakiTsushimaRotate 40-50 degrees clockwise around the southwest, at the same timeNortheastern japanIs HokkaidoShiretoko PeninsulaIt is said that it rotated 40-50 degrees counterclockwise, centering on the offshore area. As a result, the area north of Kanto in the current Japanese archipelago extends north-south, and the area west of central Japan extends east-west. This is the so-called "double door model theory". Then, about 1500 million years ago, a large depression that became the Sea of ​​Japan was formed, and the sea invaded and expanded to the size of the current Sea of ​​Japan.[*9].

From 1600 million years ago to 1100 million years ago, a fairly large area of ​​southwestern Japan (now west of the Chubu region) was land. Northeastern Japan (now the Tohoku region) was widely covered by the sea and was in the state of the archipelago. After that, northeastern Japan was uplifted by compression from the east and west by the Pacific plate and became land, and the current Ou Mountains and Dewa Hills were formed.[8].

Hokkaido was originally a continuation of northeastern Japan (now western Hokkaido)KarafutoIt is formed by joining three terrains, the north-south terrain (central Hokkaido) and the Chishima arc (eastern Hokkaido). Nansei IslandsIs the newest island arc in the Japanese island arc, which was part of the continent before 600 million years ago, but was completely separated from the continent due to a rift at the edge of the continent, and is an island arc with coral reefs. It has been since 150 million years ago[9].

There was a shallow sea between Southwest Japan and Northeast Japan, but since this eraSediment,Volcanic ejectaTohoku Japan is uplifted by being compressed from the east while being gradually filled withCentral highlands-Japan AlpsIt became. A new stratum between Southwest Japan and Northeast JapanFossa MagnaThe western edge isItoigawa Shizuoka Structural Line, The eastern edgeShibata Koide Tectonic LineとKashiwazaki Chiba Tectonic LineSo, on both sides of this tectonic line, strata of completely different times are in contact.

Thus, although imperfect, todayArc archipelagoWhat appeared in the form ofTertiaryPlioceneIt was around the beginning of. Especially after thatIce ageAt that time, the sea level dropped, and it was often connected to the continent. For exampleStrait of TartaryBecause it is shallow, Outer Manchuria, Sakhalin, and Hokkaido were often contacted by overpasses. Since the Tsugaru and Tsushima Straits are as deep as 130-140 meters, the time when they became overpasses was limited. Also,Nansei IslandsThen, both the Tokara Strait (south of Kagoshima) and the Kerama Strait (south of Okinawa Island) have a water depth of over 1000 meters.QuaternaryIt is unlikely that it became an overpass in the second half. The fact that the biota of the Nansei Islands shows the characteristics of remote islands, such as the large number of endemic species and the small number of species, is thought to be due to the extremely old age away from the continent. In the overpass problem, the Tsugaru StraitPlioceneIt was open to the end, and the Tsushima Strait was open during the opening of the Sea of ​​Japan, but is thought to have closed from the end of the Miocene to the Pliocene.[10].

The last glacial period is over, minus about 60mSoya StraitWas submerged under the surface of the seaPleistoceneFrom the end ofHoloceneThe beginning of the year, that is, about 1 to 3,000 years ago.

The current Japanese archipelago is topographically

  • The main arc of the Japanese archipelago consisting of Sakhalin, Hokkaido, Honshu, Shikoku and the surrounding islands
  • Kyushu / Ryukyu arc consisting of Kyushu and Nansei Islands
  • Eastern Hokkaido (part of)
  • Izu Peninsula (Izu / Ogasawara / Mariana ArcPart of)

And so on.

In each case, there is a narrow continental shelf on the east or south side of the island, and off the coast.Subduction zone(Trench-trough)Trench earthquakeOccurs frequently. Mountain ranges and volcanic belts are connected in parallel to this subduction zone as a whole. Elongated basins and plains are scattered between the mountains and along the sea. Japan's largest plainKanto PlainIs exceptionally wide, and the reason for its formation has not been clarified in detail, but it can be mentioned that it is located in Fossa Magna, where the depth of the basement rock is deep, and that three plates overlap. generallyEarthquakeThere are many occurrences of terrain, and there are many rugged terrains.


The Pleistocene, which began about 200 million years agoIce ageIt is also called, and the colder period (glacial period) and the warmer period (interglacial period) are repeated alternately. It was also an era of severe climate change. The resulting changes in topography and crustal movements caused by volcanic eruptions were also severe. At the height of the glacial period, the average annual temperature dropped by 7 to 8 degrees Celsius. As a result, glaciers developed in both the north and south poles, of course, but glaciers developed in the high mountains of the Northern Hemisphere and in a wide area, and the seawater decreased and the sea level dropped. The amount of decrease was about 140 m below the current sea level. However, beyond the final glacial period, the global climate has entered a period of warming, thickly deposited glaciers have begun to melt, and sea level has gradually risen.

  • Geological ageDescription of classification
    • TertiaryIs between about 6,500 million years ago and about 170 million years ago, and is further divided into Paleocene, Eocene, Oligocene, Miocene, and Pliocene. Pliocene refers to 510 million to 170 million years ago.
    • QuaternaryIs from 170 million years ago to the present, and is divided into the Pleistocene and Holocene, and is also called the human era or the human era. The Pleistocene is known as the glacial period, and the Holocene is known as the postglacial period. In Japan, the Pleistocene is sometimes called the Holocene, and the Holocene is sometimes called the Okizumi.

HoloceneThen,TemperateWarmMonsoon climateBelongs to, but in the southSubtropical climate, In the northCold temperate climateUnder the influence of[11].


Until 4000 million years agoSea of ​​JapanThe Japanese archipelago was part of the continent. About 7 years ago, from the northMammoth,Elk,reindeer,Brown bear,Pika,Red foxFrom the southNaumann Elephant,Bighorn deer,Antelope,Sika deer,Asiatic black bear,Japanese macaqueEtc. have moved. Like the animals, it is estimated that the Paleolithic people of the continent followed them and migrated from the continent. After that, when the Japanese archipelago was separated from the continent, those animals and human beings would also undergo their own evolution.

Estimated by ax-shaped stone tools

1973(Showa48 years),TokyoFuchu-shiMusashidai OfMusashidai RuinsとChibaTherefore, a ground stone tool with a polished blade was excavated. The excavated layer is in the Xth layer of Tachikawa Loam about 40,000-30,000 years ago, and its distribution covers the entire archipelago. These are the oldest examples of polishing in the world at the moment, but they were concentrated 3-4 years ago and do not appear until the early days. But thesePolished stonewareBy excavation ofPaleolithic period in the Japanese archipelagoHuman inhabitation is shown[12].

Estimated by fossil human bones

Volcanic ashJapan covered infossilIs hard to remain, and fossil human bones are rarely found.

Long time agoAichiToyohashiFound in "UshikawaIs the oldest (about 20 years ago)Old man), But2001(HeiseiThe possibility of human bones has been almost denied by the reassessment of 13) (it is considered to be animal bones such as Naumann elephants).

The oldest human skeleton found in Honshu, after a reassessment of what was previously considered a fossil human skeleton at the beginning of this century, isShizuokaHamamatsu cityExcavated inHamakita(About 1 years ago).

Found in relatively good storageOkinawaYaese TownFound at the Minatogawa quarryMinatogawaIs 1 years agoNewcomerIs. It corresponds to the Late Pleistocene or the Late Paleolithic. Slightly primitive and sturdy head and face with well-developed supraorbital and glabellar ridges, petite physique, delicate upper body, relatively sturdy lower body featuresJomon peopleIt is said that it has features that lead to.

Incidentally,JapaneseThe Jomon people, who have their roots inEurasiaIt is said that it came from.

Gene estimation

Found about 35% of the time in JapaneseY-chromosome haplogroup D1a2 strainIs considered to be the type of modern human being that first reached the Japanese archipelago, and is said to have been born in the Japanese archipelago 3.7-3.8 years ago.[13].


The Japanese archipelago and its coastal waters are one of the world's leading endemic speciesbiodiversityIt is known as an area with. In particular, the sea near Japan is the sea with the world's largest biodiversity in marine life, and 14.6% of all marine species are distributed.[14][15].. But because of Japan's high population density and developed industryEndangered speciesThere are 34 regions that are in danger of being destroyed by human beings while having extremely high biodiversity on a global scale.Hot spot) Is listed in[16].

Chronological Table

Chronology of the Japanese archipelago
Geological eraAge distributionJapanese fossilsRemarks
Precambrian era46 billion years agoUndiscoveredJapan's oldest rock (Kamiaso conglomerate, Hichiso Town, Gifu Prefecture, about 20 billion years ago)
PaleozoicCambrian5 million years agofossil 
Ordovician5 million years agofossil 
Silurian4 million years agoHalysites
Devonian4 million years agofossil 
Carboniferous3 million years agoCoral 
Permian2 million years agofossil 
MesozoicTriassic2 million years agofossil 
Jurassic2 million years agoIchthyosaur 
Cretaceous1 million years agoPlesiosaur(Futaba Squirrel)
Theropods (theropods, sauropods, ornithopoda dinosaurs, bird footprints), Sea of ​​Japan does not yet exist
CenozoicTertiaryPaleocene6500 million years agofossilK-Pg boundary(Mass extinction, Hokkaido Hombetsu)[17]
Eocene5500 million years agofossil 
Oligocene3370 million years agofossilCoalfieldFormation of
Miocene2300 million years agofossilShikoku BasinFormation, expansion of the Sea of ​​Japan, expansion of the Chishima Basin[18]
2000-1000 million years ago Volcanic activity on the Sea of ​​Japan side of northeastern Japan (Green toughFluctuation), the Sea of ​​Japan opens, and the prototype of the Japanese archipelago can be created[19]
1000 million years ago Due to a collisionHidaka MountainsFormation of
Pliocene500 million years agofossilSea of ​​JapanExpansion of
QuaternaryPleistocene180 million years agoNaumann ElephantOn the Sea of ​​Japan sideFold obiFormation of
50 million years ago Izu PeninsulaDue to a collisionTanzawa areaFormation of
Holocene1 million years agofossilMost平野Formation, about 7300 years agoOnikai CalderaAkahoya eruption

Japan and the Japanese archipelago

The origin of the name of the Japanese archipelagoJapanIs. In ancient Japan, "Great island country, great eight island countryWas also called (Oyashima no Kuni)[*10].

Even now, the main country of JapanterritoryIt is sometimes used to express Japan from a geographical point of view. In the consciousness of the Japanese people, "Japanese archipelago" and "Japan" may be equated.


[How to use footnotes]

注 釈

  1. ^ [Reference] Among these, up to the 30th place in the "Area ranking of islands in the world"(I.e. (Source List of islands by area Than)
    3rd place·Borneo(Indonesia-Malaysia-Eur-lex.europa.eu eur-lex.europa.eu Of 3 countriesterritoryIsland), 7th placeHonshu(Japan's largest island), 11th placeSulawesi(Island with the 4th largest area in Indonesia), 15thLuzon(フィリピンLargest island), 19th placeMindanao(The second largest island in the Philippines), 2stHokkaido(The second largest island in Japan), 2rdSakhalin Island(ロシアLargest island).
  2. ^ In the same areaKuril IslandsThere are many islands including. On this page, "Islands around the Japanese Archipelago (Far East・ Refer to the photo and explanation of "Islands in the coastal area)".
  3. ^ The plane shape is an arc shape, and it is a row of islands extending in an arc shape, between it and the ocean floor.TrenchortroughRefers to the existence of.
    <Source> Nobuyuki Yonekura "Large Topography in and Surrounding the Japanese Archipelago" / Nobuyuki Yonekura, Sohei Kaizuka, Michio Nogami, Kiyotaka Chinzei, "Japanese Topography 1 Overview", University of Tokyo Press 2001, page 2.
  4. ^ "Kojien''Daijirin], Etc., the definition of "Japanese archipelago" is the archipelago consisting of Hokkaido island, Honshu island, Shikoku island, Kyushu island and the islands associated with them.
  5. ^ "Kojien』(Iwanami ShotenAccording to the definition of the item "Japanese Archipelago" published in January 2008, 1th edition), it is an archipelago consisting of Hokkaido Island, Honshu Island, Shikoku Island, Kyushu Island and attached islands. It forms an arc along the eastern edge of the Asian continent. Geomorphologically,Northeastern japanArcSouthwest JapanArc ...Ryukyu arcEtc. are broadly referred to. It is written.
  6. ^ According to the "Kuril Islands" section of "Concise Japan Geographical Dictionary 3rd Edition" (Sanseido, published in December 1989), edited by Takeo Tanioka and Keiichiro Yamaguchi, edited by Sanseido.Kamchatka PeninsulaThe arc-shaped archipelago between Hokkaido and Hokkaido. North on the southeast sideThe Pacific Ocean, Northwest sideSea of ​​OkhotskDivide into. The main islandsShumshu Island-Alite Island-Paramushir Island-Onekotan Island-Shascotan Island-Matua-Rashova Island-Kate island-Cincil Island-Urup Island-Etorofu Island-Kunashiri Island.. 1875 (Meiji 8)Karafuto Chishima Exchange TreatyBecame a Japanese territory, but JapanSan Francisco Peace TreatyAbandoned territorial rights. "
  7. ^ According to the "Kuril Islands" section of "Kojien" (Iwanami Shoten, published in January 2008, 1th edition), "Arc-shaped archipelago extending from the eastern end of the main island of Hokkaido to the southern end of the Kamchatka Peninsula. Kunari Island. Etorofu (above the South Kuril Islands), Tokubashi Island (Uruppu), Shinchi Island (Shimushiru), Ketoi Island, Rashowa Island, Matsuwa Island (Matsu) W), Shashikotan, Onnekotan (Nakachishima), Parashimuru, Shimusu, Arai And) (above Kita-Kuril Islands) etc.Second World WarLaterロシア(OldUSSR) Is under control. It is described as "Kuril Islands".
  8. ^ The eastern part of the Asian continent is considered to be a region that has been divided and expanded since 3000 million years ago due to crustal movements. One of the ruptures on the eastern side of the continent has occurred 1 million years ago at the location of the Sea of ​​Japan. The rupture gradually became larger, and the prototype of the Sea of ​​Japan was completed. And by 1900 million years ago, the Sea of ​​Japan had expanded to its current size (Makoto Sahara, Supervised by Werner Steinhaus, National Research Institutes for Cultural Properties Nara Institute of Cultural PropertiesEdited "German Exhibition Memorial Overview Japanese Archeology (Popular Edition) Volume XNUMX"Student company 2007 P.20).
  9. ^ In support of the double-door model theory, the strata where the magnetic poles at the time of deposition are recordedGeomagnetismThere is a change in the declination of the pattern.
  10. ^ [Reference] Japan's oldestHistory book "Record of Ancient Matters』(712In the offering), Japan is called "Oyashima no Kuni" and is a general term for the following "eight islands" (Oyashima no Kuni).Domestic production # Island production).
    In order of appearance, in modern name notation,Awaji,Shikoku,Oki Islands,Kyusyu,Iki,Tsushima,Sado,Honshu, More than 8 islands. (After this, 6 more islands will be introduced. The names of these 14 islands in the original text areComparison table of "Kojiki" and "Nihonshoki"(See)
    Also,"Japanese calligraphy』(720In Completion), Japan is described as "Oyashima no Kuni".
    The meaning of "Daiyashima country / Daihachishu country" is not "a country consisting of eight islands" but "a country consisting of many islands".(*)
    That is, in ancient Japan and Japanese mythology, "eight" was used as an analogy to the holy number, vaguely large number, and many. 8 # Other 8.. (Example: "Yaezakura", "Eight million gods" Many gods , "To Chiyo, to Yachiyo eternally , "Yakumo Clouds folded over and over ",And so on)
    (*) Kojien-Daijirin-DaijisenEtc. also means "a country consisting of many islands".


  1. ^ DaijirinThird sales item "Japanese Archipelago"
  2. ^ Some areas are effectively controlled by Russia and the Republic of Korea
  3. ^ "Japanese Archipelago", World Encyclopedia, Heibonsha, (2009) 
  4. ^ Daijirin XNUMXrd Edition Japanese Archipelago, Digital Daijisen Japanese Archipelago
  5. ^ Volcanoes of the world, Cabinet Office, http://www.bousai.go.jp/kazan/taisaku/k101.htm 
  6. ^ Takeo Tanioka-Keiichi YamaguchiSupervised by Sanseido Editorial Office, "Concise Japanese Place Name Dictionary, 3rd Edition" (Sanseido, Published in December 1989), based on the item "Japanese Archipelago".
  7. ^ Microsoft Encarta Comprehensive Encyclopedia2003 From the item "Japan"NCID BA85593287.Online version(Retrieved September 2007, 2)[Broken link].
  8. ^ Makoto Sahara, Supervised by Werner Steinhaus, National Research Institutes for Cultural Properties Nara Institute of Cultural PropertiesEdited "German Exhibition Memorial Overview Japanese Archeology (Popular Edition) Volume XNUMX"Student company 2007 P.20-21
  9. ^ Makoto Sahara, Supervised by Werner Steinhaus, National Research Institutes for Cultural Properties Nara Institute of Cultural PropertiesEdited "German Exhibition Memorial Overview Japanese Archeology (Popular Edition) Volume XNUMX"Student company 2007 P.22
  10. ^ Makoto Sahara, Supervised by Werner Steinhaus, National Research Institutes for Cultural Properties Nara Institute of Cultural PropertiesEdited "German Exhibition Memorial Overview Japanese Archeology (Popular Edition) Volume XNUMX"Student company 2007 P.29-30
  11. ^ Nobuyuki Yonekura, Sohei Kaizuka, Michio Nogami, Kiyotaka Chinzei, "Review of Japan's Topography 1", University of Tokyo Press, 2001, page 2.
  12. ^ Shizuo Oda "Paleolithic Polished Stone Ax"
  13. ^ Shi, Hong; Zhong, Hua; Peng, Yi; Dong, Yong-li; Qi, Xue-bin; Zhang, Feng; Liu, Lu-Fang; Tan, Si-jie; Ma, Runlin Z; Xiao, Chun-Jie Wells, R Spencer; Jin, Li; Su, Bing (October 29, 2008). "Y chromosome evidence of earliest modern human settlement in East Asia and multiple origins of Tibetan and Japanese populations". BMC Biology (BioMed Central) 6: 45. doi: 10.1186 / 1741-7007-6-45. PMC 2605740. PMID 18959782.Retrieved November 21, 2010.
  14. ^ Biodiversity hotspots in the waters near Japan ~ 14.6% of all marine species are distributed ~
  15. ^ 3 species of marine life in the waters near Japan, one of the most diverse in the world
  16. ^ Biodiversity Hotspot | JAPAN HOTSPOT-Biodiversity Information Site
  17. ^ Motomaro Shirao, Takashi Kobata, Yasuji Saito, "New Edition 20 Billion Years of the Japanese Islands-50 Selections of Landscapes-" Iwanami Shoten, page 2009 of 7
  18. ^ Motomaro Shirao, Takashi Kobata, Yasuji Saito, "New Edition 20 Billion Years of the Japanese Islands-50 Selections of Landscapes-" Iwanami Shoten, page 2009 of 6
  19. ^ Yamato Omine Research Group, "Mt. Omine / Mt. Odaigahara-Natural people and people's friendship-" Tsukiji Shokan, p. 2009, 61)


Related item

外部 リンク

At the beginning of this movie, the origin of the Japanese archipelago is explained. For more information on this movie, see "History of Japan-Movie "Birth of Japan-History of the People-"See


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