Portal field news

Portal field news


🌤 | Expected to have many sunny days this week The season will advance after rain next week


Expected to have many sunny days this week The season will advance after rain next week

If you write the contents roughly
However, it is likely to rain in parts of the Sea of ​​Japan side and the Izu Islands.

Today 16th (Tuesday), from Sanin to Hokuriku, the weather will be cloudy in northern Japan, and it will rain in some places. … → Continue reading

 Weather map

It is a weather map of a weather information company.We will deliver news articles written by weather forecasters about daily weather and disaster prevention information for heavy rains and typhoons.

Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.

Izu Islands

Izu Islands(Izushoto)The Pacific Ocean(Philippine Sea)Tokyo OfislandsIt is a department. There are also manned islands, and the southern islands are under climatic conditions called everlasting spring. Each island has different characteristics and is famous for island sushi, ashitaba, dolphins, fishing, surfing, hot springs, mountain climbing, and astronomical observation.

Izu PeninsulaSoutheast ofizu-OshimaからLot's WifeOver 100 in betweenislandsConsists of. SouthernmostBayonnaise Rocks,Smith Island,Torishima, Lot's WifeIzu Islands(Zunanshotou) "is also called.Administrative divisionAs anyTokyoHowever, from the historical background, "Izu IslandsThe name is well established. Also, apart from these geographical and administrative names,Izu NanashimaThe name (Izushi Chito) is commonly used.

Currently, the number of islands (manned islands) where people settle is nine. Besides OshimaToshima-Niijima-Shikinejima-Kozushima-Miyakejima-Mikurajima-Hachijojima-AogashimaThat is the eight islands of. Long time agoUdoneshima,Hachijo Kojima・ There was a permanent resident in Torishima, but nowUninhabited islandIt has become. Also,Jinai Island-Hayashima-Onohara Island-Inambajima-Bayonnaise Rocks-Smith Island-Lot's WifeIsRecorded historyIt has been an uninhabited island since then.

North of Hachijojima in the Izu IslandsFuji Hakone Izu National ParkBelongs to[2].


The straight line distance from Tokyo to Lot's Wife is about 650km. mostNorthOshima, located in, is the southernmost tip of the Izu Peninsula.IrozakiTo the north ofSagami NadaIt is an island off the coast of Izu Peninsula and east of the Izu Peninsula, and has the largest area of ​​the Izu Islands (on sunny nights, you can see the lights of cars running along the coast of the Izu Peninsula). From here to the southwest, alongside Toshima, Niijima, Shikinejima, and Kozushima,ZenisuContinue until. This rise that continues below sea levelZenisu RidgeIs called. 40 east-southeast of KozushimakmMiyakejima is about 60km south-southeast of Oshima, and Mikurajima is about 20km south of Miyakejima. Located about 100km south of MikurajimaGourdThe shaped island is Hachijojima, and Aogashima is about 70km south of Hachijojima. Aogashima is the southern limit of manned islands in the Izu Islands, and the islands south of this (Bayonnaise Rocks, Smith Island, Torishima, Lot's Wife, etc.) are uninhabited islands.

Since the Izu Islands are long from north to south, they are sometimes divided into northern and southern parts in terms of weather and fisheries. In that case, the northern part of the Izu Islands is from Oshima to Kozushima, and the southern part of the Izu Islands is from Miyakejima to Aogashima. When expressing it in more detail, it may be expressed as "Southern Izu Islands" Miyakejima region.

KuroshioIs 50-100km wide and has a flow velocity of 7 near the passage through the Izu Islands.knot(Approximately 13km / h). Usually, it often flows between Miyakejima and Hachijojima,MeanderThen, it may pass through the south of Hachijojima and the sea near Oshima.

All the islands of the Izu IslandsVolcanoOrcalderaformulaSubmarine volcanoThe outer ring of the mountain is higher than the sea level. In particular, Aogashima is a typical double volcano that is rare in the world and can be seen at a glance, and there is a small volcano called Maruyama in the crater. There are old and stable islands like Mikurajima,1983 2000 Miyakejima1986 Some islands, such as Oshima, have repeated active volcanic activity.

Administrative division

The administrative divisions are all islandsTokyoAs a local agencyTokyo Metropolitan GovernmentIs a sub-organization ofOshima Branch,Miyake Branch,Hachijo branch officeIs placed. Of TokyoislandsArea isTokyo islandsIt is called, but in Tokyo there is a "嶼"Common kanjiBecause it is outside, it is written as "Island".

in Japantown,village ThecountyWith the exception of the Izu Islands, there are no counties. Therefore, the official address will be displayed as "Oshima-cho, Tokyo". In Hachijo Town and Miyake Village, the notation "Hachijo Town, Hachijo Island, Tokyo" is commonly used.

The jurisdiction of each branch office is shown below. The numbers in parentheses are the major islands in each town / village area.

other than this,Bayonnaise RocksThe islands from to Lot's Wife are under the direct jurisdiction of the Tokyo Metropolitan Government due to the affiliation dispute between Aogashima Village and Hachijo Town. These uninhabited islands are one of the few exceptions that do not belong to the municipalities, which are the smallest units of local autonomy in Japan.

Historically, the Izu IslandsSuruga countryLaterIzukuniBelongs to中 世Until Izu ProvinceKamo-gunIt was in Mishima Township. Following the trend since modern timesShizuokaIt does not belong to, but belongs to Tokyo. In fact, once I belonged to Shizuoka prefectureTokyoIt has been transferred to (at that time). There is a theory that this is because Tokyo's finances were more affordable than Shizuoka, but as will be described later.Edo PeriodThe route is fromEdoIt is said that the biggest reason is that Edo (Tokyo) was closer to both physical and human exchanges (""#historySee section). In addition, it should be notedMeijiWhen it was incorporated into Shizuoka Prefecture during the era, there was a movement centered on islanders and merchants to plead for belonging to Tokyo Prefecture.

Regional language


Izu IslandsPhilippine Sea PlateOn the eastern edge of the Philippine Sea PlatePacific plateSinksIzu/Ogasawara TrenchRuns north and south off the eastern coast of the islands. That is, the Izu IslandsIzu, Ogasawara, Mariana Island ArcIt forms part of an island arc called. plateIn the fire activity accompanying the subduction ofVolcanic islandAn island arc consisting of was developed. The rocks that make up the islandsIzu Oshima Miharayama,Miyakejima OyamaOn behalf ofbasaltHowever, Niijima and Shikinejima are rare in the world.Koga stoneTo give birth toRhyoliteAnd KozushimaobsidianConsists of rhyolite with.

島 々

Specifications of the islands of the Izu Islands
imageIsland nameArea (km2)Population (people)Summit (m)Peak nameCoordinate
Landsat IzuOshima Island.jpgizu-Oshima91.067,411 people (end of December 2020)764Mihara34°44'N 139°24'E /34.733 degrees north latitude 139.400 degrees east longitude / 34.733; 139.400 (Izu-Ōshima)
Landsat Toshima Island.jpgToshima4.12304 people (2007)508Miyatsukayama34°31'N 139°17'E /34.517 degrees north latitude 139.283 degrees east longitude / 34.517; 139.283 (Toshima)
Utone shima.jpgUdoneshima0.4Unmanned[Table Note 1]210 North Latitude 34 Degrees 28 Minutes 21 Seconds East longitude 139 degree 17 min 38 sec /34.47250 degrees north latitude 139.29389 degrees east longitude / 34.47250; 139.29389 (Udoneshima)
Landsat Niijima and Shikinejima Island.jpgNiijima(WhenJinai IslandHayashima23.872,420 people (2007)432Miyatsukayama34°22'N 139°16'E /34.367 degrees north latitude 139.267 degrees east longitude / 34.367; 139.267 (Nii-jima)
Shikine-jima aerial.jpgShikinejima3.9600 people (2007)109Kamibikiyama34°19.5'N 139°13'E /34.3250 degrees north latitude 139.217 degrees east longitude / 34.3250; 139.217 (Shikine-jima)
Landsat Kozushima Island.jpgKozushima18.481,914 people (2007)574Tenjosan34°13'N 139°9'E /34.217 degrees north latitude 139.150 degrees east longitude / 34.217; 139.150 (Kōzu-shima)
Landsat Miyakejima Island.jpgMiyakejima55.442,382 people (2007)815Mt. Oyama34°5'N 139°32'E /34.083 degrees north latitude 139.533 degrees east longitude / 34.083; 139.533 (miyake-jima)
Ohnoharajima mlit1978.jpgOnohara Island0.2Unmanned114KoyaneNorth Latitude 34 Degrees 02 Minutes 53 Seconds East longitude 139 degree 23 min 02 sec /34.04806 degrees north latitude 139.38389 degrees east longitude / 34.04806; 139.38389 (Ohnohara-jima)
Landsat Mikurajima Island.jpgMikurajima20.58313 people (2007)85133°52.5'N 139°36'E /33.8750 degrees north latitude 139.600 degrees east longitude / 33.8750; 139.600 (Mikura-jima)
Inambashima mlit.jpgInambajima0.005Unmanned74 North Latitude 33 Degrees 38 Minutes 53 Seconds East longitude 139 degree 18 min 08 sec /33.64806 degrees north latitude 139.30222 degrees east longitude / 33.64806; 139.30222 (Inamba-jima)
Hachijo branch office
Landsat Hachijojima Island.jpgHachijojima62.528,363 people (2007)854(alias:)33°7'N 139°47'E /33.117 degrees north latitude 139.783 degrees east longitude / 33.117; 139.783 (Hachijō-jima)
Hachojyo-kojima mlit1978.jpgHachijo Kojima3.08Unmanned[Table Note 2]616.8OhirayamaNorth Latitude 33 Degrees 7 Minutes 31 Seconds East longitude 139 degree 41 min 18 sec /33.12528 degrees north latitude 139.68833 degrees east longitude / 33.12528; 139.68833 (Hachijō-kojima)
Landsat Aogashima Island.jpgAogashima8.75192 people (2007)423(I.e.North Latitude 32 Degrees 27 Minutes 29 Seconds East longitude 139 degree 46 min 04 sec /32.45806 degrees north latitude 139.76778 degrees east longitude / 32.45806; 139.76778 (Aogashima)
Bayonaise Rocks mlit.jpgBayonnaise Rocks
0.01Unmanned9.9 North Latitude 31 Degrees 53 Minutes 14 Seconds East longitude 139 degree 55 min 03 sec /31.88722 degrees north latitude 139.91750 degrees east longitude / 31.88722; 139.91750 (Bayonnaise Rocks)
Smithisland milt.jpgSmith Island0.03Unmanned136 North Latitude 31 Degrees 26 Minutes 13 Seconds East longitude 140 degree 02 min 49 sec /31.43694 degrees north latitude 140.04694 degrees east longitude / 31.43694; 140.04694 (Sumisu-jima)
Tori-Shima Island of Izu-Islands Aerial photograph.2001.jpgTorishima4.79Unmanned[Table Note 3]394North Latitude 30 Degrees 28 Minutes 48 Seconds East longitude 140 degree 18 min 22 sec /30.48000 degrees north latitude 140.30611 degrees east longitude / 30.48000; 140.30611 (Torishima)
Soufuiwa.jpgLot's Wife0.0037Unmanned99 North Latitude 29 Degrees 47 Minutes 39 Seconds East longitude 140 degree 20 min 31 sec /29.79417 degrees north latitude 140.34194 degrees east longitude / 29.79417; 140.34194 (Sōfugan)
  1. ^ Udoneshima TheMeiji EraLived in.
  2. ^ Unmanned since 1969 (at that time, population 31, peak 513)
  3. ^ Torishima, The largest of the uninhabited islands. A volcanic eruption in 1902 killed all 125 islanders. 1965 Uninhabited island.


The population of the Izu Islands is declining more slowly than the average in Japan.[3]

Population change[3]
YearsIzu IslandsRemote islands of JapanJapan total


For the northJomon PeriodThere are traces of people living in Tsunoshima, and Jomon archaeological sites have been discovered on each island. Furthermore, the Yayoi ruins have been discovered on Miyakejima, suggesting that settlement had begun during this period.Yayoi PeriodcharacteristicRice cultivationAs for culture, it will flourish after the ruins are built.

Official house,samurai,MonkNoble people such asExileBecause it was often swept away byCapital of KyotoCulture and customs were often brought in.

Edo Period TheHeavenwas. Although it is an area of ​​the former Izu province, buying and selling of products etc.EdoIsland placed onClubhouseBecause it was done through, it has a strong connection with Edo, which was incorporated into Tokyo Prefecture in 1878.Kanto regionIt becomes a factor to be incorporated in a part of.

Old timesIzu GoshimaorIzu YashimaIt seems that it was sometimes called, but by the end of the Edo periodIzu NanashimaThe name was well established. Since then, this has become commonplace and is often used as a term to refer to the entire Izu Islands. However, it does not match the situation of counting 9 islands only on the islands where people settle.

Chronological table

History since modern times

  • MeijiAs of the first year, the entire area is under the jurisdiction of the Izu DaikanShogunateMet. (24 villages)
Chiyuki(I.e.Number of villagesName of the village
Shogunate(I.e.Village 6Okada Village, Motomura, Izumizu Village, Nomasu Village, Sashikiji Village, Hauki Port Village
ToshimaVillage 1Toshima
NiijimaVillage 2Niijima Honmura, Wakago Village
KozushimaVillage 1Kozushima
MiyakejimaVillage 5Izu Village, Kamitsuki Village, Igaya Village, Ako Village, Tsubota Village
MikurajimaVillage 1Mikurajima
HachijojimaVillage 5Okago Village, Mine Village, Kashidate Village, Nakanogo Village, Sueyoshi Village
Hachijo KojimaVillage 2Toriuchi Village, Utsugi Village
AogashimaVillage 1Aogashima


In the Izu IslandsMiku Miyamiya Stag,Plestiodon latissisSuch asEndemic speciesThere are also many.Healthy vegetablesAttracting attention asAshitaba (Ashitaba)Is said to have originated in the Izu Islands. In the seaDolphin,A whaleYou can also seeTorishima TheAlbatrossKnown as.

However, it is very different in biota from the Ogasawara Islands in the south.[11].. The biota of the Ogasawara IslandsEndemic speciesThere is a large number of adaptive radiations in certain taxa, while there are several biotas that are largely lacking.Ocean islandIt has the characteristics of biota that are often found in. On the other hand, that of the Izu Islands is rather close to the biota of mainland Japan. For example, there are no snakes in the Ogasawara Islands, but in the Izu Islands.Striped snake,Rat snake,Jim Guri,MamushiEtc., all of which are considered to be the same species as those in Honshu[12].. The lizards of the Izu IslandsPlestiodon latissisIt was a different species from that of Honshu, but it was recently discovered that it is distributed from the Izu Islands to the Izu Peninsula. However, this cannot always be regarded as evidence that it has been geographically separated from the Izu Peninsula-type Honshu. In recent years, it has been confirmed that other lizards in mainland Japan are also divided into two species, north and south. There are other endemic species, but many have species closely related to Honshu.

In any case, the biota of the Izu Islands is closely related to that of the Izu Peninsula, and has a very strong affinity with other parts of the mainland. For example, in the volcanic gravel of the Izu Islands, there are grasslands dominated by Japanese knotweed and Japanese knotweed, and both of these species are endemic to the Izu Islands (the former is a subspecies and the latter is a species). , Shimatanukiran is very closely related to Kotanukiran, which grows from the deciduous forest zone to the alpine zone in Honshu, and the Japanese knotweed, which is a basic variant of the Japanese knotweed, is also distributed from the Japanese archipelago (Amami Oshima in the southern limit) to China. is there[13].. Such grassland plant communities are believed to be derived from plant communities above the temperate regions of Honshu. To explain this, at some point in the past, the Izu Islands and Honshu were on the same land, and at that time the Izu Islands were covered with summer green broad-leaved forests due to the cold climate, but later seawater. It is safe to see that the surface has risen to become an island and speciation has progressed due to isolation. This way of thinking has been raised from the research of insect fauna and terrestrial shellfish fauna, and a huge peninsula including from the Izu Peninsula to Aogashima in the Izu Islands is assumed, and the name Koizu Peninsula is given. Has been done.


It depends on the island, butFishery:-Agriculture:-TourismIs the center. In the same areaFishing villages and rural areasThere are some islands that should be considered to coexist. In the past in TorishimaAlbatrossCapture and bird droppings (guano) Was also collected.

Special product



Mainly from the following ports to each islandTokai KisenEtc.Freighter(HydrofoilBoeing 929 "Jetfoil") Has a regular route.Temporary routes may be provided depending on the season.なお、青ヶ島の定期航路はIn addition, the regular route of AogashimaIzu Islands DevelopmentOnly the ferry from Hachijojima operated by.伊豆諸島航路には下田航路を運用するOperate the Shimoda route for the Izu Islands routeFerry AzeriaExcept forCar ferryDoes not exist, so vehicles can only be transported as cargo.


  • On HachijojimaHaneda airportCan go back and forth between空港There,All Nippon Airways Operates as an (ANA) flight. Previously, flights connecting Oshima and Miyakejima to Haneda Airport were also operated by ANA, but Miyakejima flights were abolished on March 2014, 3 and transferred to New Central Airservice. The Oshima flight was also abolished in October 31.
  • (I.e.,Niijima,Kozushima,MiyakejimaToChofu Airfield(TokyoChofu City) To and fromCommuter aviationFlightNew Central AirlinesIt is operated by.
  • Tokyo Air Land ShuttleAogashima ⇔ Hachijojima ⇔ Mikurajima ⇔ Miyakejima ⇔ Oshima ⇔ Helicopter that goes back and forth between Toshima and each island (helicopterBy commuter airlines)Toho AirlinesIt is operated by. Helicopter every morningHachijojima AirportImmediately after the first flight from Haneda Airport (ANA1) departs, it will fly from Hachijojima Airport to Aogashima, and after returning, it will depart again to Mikurajima. After that, each island will be operated by the above route, and the day's operation will be completed by returning from Mikurajima to Hachijojima in the evening. Of these, Aogashima and Mikurajima may be operated on special flights before and after the regular flights on the day when requested by the village office due to reasons such as the cancellation of shipping services due to bad weather. The fare is not cheap, but for Toshima, Mikurajima, and Aogashima, which originally have no airport, it is the only means of transportation other than shipping, especially because there are no direct flights to and from Tokyo, and the service rate of connecting ships is very low. Therefore, it has become a valuable presence for travelers between Hachijojima and Aogashima (Toshima is also often canceled in winter).

Island traffic

There is no railroadTransit Bus,Taxi,Car rental, Bicycle rental is the main means of transportation. If the island does not have a fixed-route bus, contact the accommodation you booked in advance and a car will be arranged at the port.

Transit Bus


[How to use footnotes]

注 釈

  1. ^ Regime:legislation-judicial-AdministrationThe authority to exercise the three powers of.
  2. ^ In a broad senseJapanese archipelagoAll the shochu made in the islands of Tokyo is "island shochu". In a narrow sense, it refers only to those of the Izu Islands.


  1. ^ a b c d "What is the Izu Islands?”. Kotobank. 2018/3/31Browse.
  2. ^ *From the area map of the official website of Fuji Hakone Izu National Park, Ministry of the Environment
  3. ^ a b Gotoh, H .; Maeno, Y .; Takezawa, T .; Murata, T .; Takahashi, N. (2010). “Infrastructure maintenance and disaster prevention measures on isolated Islands: the case of the Izu Islands near tokyo”. In Favro, S .; Brebbia, CA. Island Sustainability. WIT transactions on ecology and the environment (Vol. 130). WIT Press. ISBN 978-1-84564-434-5. https://books.google.com/books?&id=Kc5xrqAD9fYC&pg=PA185 
  4. ^ "Japanese Historical Place Names 22 Place Names in Shizuoka Prefecture" Heibonsha, 2000.ISBN 4582490220.. Item of "Izu Province" (P75.).
  5. ^ 4th year of Meiji 594th Declaration No. XNUMX - National Diet LibraryModern digital library
  6. ^ 9th year of Meiji 53th Declaration No. XNUMX -National Diet Library Modern Digital Library
  7. ^ 11th year of Meiji 1th Declaration No. XNUMX -National Diet Library Modern Digital Library
  8. ^ a b "Government Bulletin" No. 7352, December 40, 12 "Ministry of Interior Ordinance No. 28 of 40"
  9. ^ "Government Bulletin" No. 3281, July 12, 7 "Taisho 7 Interior Ministry Ordinance No. 12"
  10. ^ Overview of Tokyo Island Promotion Corporation
  11. ^ Below, Shiba (2016)
  12. ^ Uchiyama et al. (2002)
  13. ^ Satake et al. (1982), p.24


  • Masahiro Shiba "Did the Izu Peninsula come from the south?", (2016) ,: Journal of Fossil Research, Vol.49 (1): p.35-43.
  • Ryu Uchiyama et al. "Definitive Japanese Amphibian Reptiles", (2002), Heibonsha

Related item

外部 リンク


Back to Top