Tokyo Tokyo Metropolis, one of the 47 prefectures of Japan, has served as the Japanese capital since 1869. As of 2018, the Greater Tokyo Area ranked as the most populous metropolitan area in the world; the urban area houses the seat of the Emperor of Japan, of the Japanese government and of the National Diet. Tokyo forms part of the Kantō region on the southeastern side of Japan's main island and includes the Izu Islands and Ogasawara Islands. Tokyo was named Edo when Shōgun Tokugawa Ieyasu made the city his headquarters in 1603, it became the capital after Emperor Meiji moved his seat to the city from Kyoto in 1868. Tokyo Metropolis formed in 1943 from the merger of the former Tokyo Prefecture and the city of Tokyo. Tokyo is referred to as a city but is known and governed as a "metropolitan prefecture", which differs from and combines elements of a city and a prefecture, a characteristic unique to Tokyo; the 23 Special Wards of Tokyo were Tokyo City. On July 1, 1943, it merged with Tokyo Prefecture and became Tokyo Metropolis with an additional 26 municipalities in the western part of the prefecture, the Izu islands and Ogasawara islands south of Tokyo.
The population of the special wards is over 9 million people, with the total population of Tokyo Metropolis exceeding 13.8 million. The prefecture is part of the world's most populous metropolitan area called the Greater Tokyo Area with over 38 million people and the world's largest urban agglomeration economy; as of 2011, Tokyo hosted 51 of the Fortune Global 500 companies, the highest number of any city in the world at that time. Tokyo ranked third in the International Financial Centres Development Index; the city is home to various television networks such as Fuji TV, Tokyo MX, TV Tokyo, TV Asahi, Nippon Television, NHK and the Tokyo Broadcasting System. Tokyo third in the Global Cities Index; the GaWC's 2018 inventory classified Tokyo as an alpha+ world city – and as of 2014 TripAdvisor's World City Survey ranked Tokyo first in its "Best overall experience" category. As of 2018 Tokyo ranked as the 2nd-most expensive city for expatriates, according to the Mercer consulting firm, and the world's 11th-most expensive city according to the Economist Intelligence Unit's cost-of-living survey.
In 2015, Tokyo was named the Most Liveable City in the world by the magazine Monocle. The Michelin Guide has awarded Tokyo by far the most Michelin stars of any city in the world. Tokyo was ranked first out of all sixty cities in the 2017 Safe Cities Index; the QS Best Student Cities ranked Tokyo as the 3rd-best city in the world to be a university student in 2016 and 2nd in 2018. Tokyo hosted the 1964 Summer Olympics, the 1979 G-7 summit, the 1986 G-7 summit, the 1993 G-7 summit, will host the 2019 Rugby World Cup, the 2020 Summer Olympics and the 2020 Summer Paralympics. Tokyo was known as Edo, which means "estuary", its name was changed to Tokyo when it became the imperial capital with the arrival of Emperor Meiji in 1868, in line with the East Asian tradition of including the word capital in the name of the capital city. During the early Meiji period, the city was called "Tōkei", an alternative pronunciation for the same characters representing "Tokyo", making it a kanji homograph; some surviving official English documents use the spelling "Tokei".
The name Tokyo was first suggested in 1813 in the book Kondō Hisaku, written by Satō Nobuhiro. When Ōkubo Toshimichi proposed the renaming to the government during the Meiji Restoration, according to Oda Kanshi, he got the idea from that book. Tokyo was a small fishing village named Edo, in what was part of the old Musashi Province. Edo was first fortified in the late twelfth century. In 1457, Ōta Dōkan built Edo Castle. In 1590, Tokugawa Ieyasu was transferred from Mikawa Province to Kantō region; when he became shōgun in 1603, Edo became the center of his ruling. During the subsequent Edo period, Edo grew into one of the largest cities in the world with a population topping one million by the 18th century, but Edo was Tokugawa's home and was not capital of Japan. The Emperor himself lived in Kyoto from 794 to 1868 as capital of Japan. During the Edo era, the city enjoyed a prolonged period of peace known as the Pax Tokugawa, in the presence of such peace, Edo adopted a stringent policy of seclusion, which helped to perpetuate the lack of any serious military threat to the city.
The absence of war-inflicted devastation allowed Edo to devote the majority of its resources to rebuilding in the wake of the consistent fires and other devastating natural disasters that plagued the city. However, this prolonged period of seclusion came to an end with the arrival of American Commodore Matthew C. Perry in 1853. Commodore Perry forced the opening of the ports of Shimoda and Hakodate, leading to an increase in the demand for new foreign goods and subsequently a severe rise in inflation. Social unrest mounted in the wake of these higher prices and culminated in widespread rebellions and demonstrations in the form of the "smashing" of rice establishments. Meanwhile, supporters of the Meiji Emperor leveraged the disruption that t
The Izu Islands are a group of volcanic islands stretching south and east from the Izu Peninsula of Honshū, Japan. Administratively, they form six villages; the largest is Izu Ōshima called Ōshima. Although traditionally referred to as the "Izu Seven", there are in fact more than a dozen islands and islets. Nine among them are inhabited; the Izu islands stretch south-east from the Izu Peninsula on Honshu and cover an area of 301.56 km2. There are nine populated islands with a total population of 24,645 people spread over 296.56 km2. The largest of them is Izu Oshima, the smallest Toshima Of the inhabited islands, seven are traditionally referred to as the "Izu Seven": Oshima, Niijima, Miyakejima and Mikurajima, though Shikinejima and Aogashima are sometimes included as well; each of the islands has its unique character: Oshima is noted for its active volcano Mt Mihara and camellias, Hachijojima for its former penal colony, Mikurajima for dolphin watching, Niijima for its numerous beaches, Kozujima for its white sandy shores, Hachijojima for its well-preserved unique culture, Miyakejima for the 2001 volcanic eruption.
During the Edo period, Nii-jima, Miyake-jima, Hachijō-jima served as places of exile for criminals. The subtropical Ogasawara Islands, which are administratively part of Tokyo, lie further to the south, they form a far-flung archipelago of over thirty islands some 1,000 km due south of Tokyo. 1) Udone-shima was inhabited during the Meiji era.2) Uninhabited since 1969 3) Tori-shima, the largest of the uninhabited islands, had a population of 150 until 1902, when all were killed by a volcanic eruption. Since the island has been uninhabited; the Izu Islands are divided into two towns and six villages Three subprefectures are formed above the municipalities as branch offices of the metropolitan government. All the islands lie within the Fuji-Hakone-Izu National Park; the four southernmost islands are not administrated under any town or village in Hachijō Subprefecture, but are unincorporated areas. Torishima is an important bird refuge. Deserted islands between Aogashima and Ogasawara Islands, namely Bayonaise Rocks, Smith Island and Lot's Wife do not belong to any municipality, because both Hachijō Town and Aogashima Village claim administrative rights.
They are directly controlled by Hachijō Subprefecture instead. Ōshima Subprefecture Ōshima Town: Izu Ōshima Toshima Village: Toshima Niijima Village: Niijima and Udoneshima Kōzushima Village: Kōzushima Miyake Subprefecture Miyake Village: Miyakejima and Ōnoharajima Mikurajima Village: Mikurajima, Inambajima Hachijō Subprefecture Hachijō Town: Hachijōjima and Hachijōkojima Aogashima Village: Aogashima unincorporated: Bayonnaise Rocks, Sumisu-tō, Sōfu-iwa Though the population on the Izu Islands has been dropping, the phase is less dramatic than on other isolated Japanese islands. The primary industries are fisheries and tourism; the most scenic spots on the islands are crowded with tourists during summers. Popular tourist activities include swimming, scuba diving, fishing, bird watching and trekking. Transportation between the islands, by cargo-passengers boats and aircraft, is supported by harbours on all inhabited islands and five airports. There are 5 airports, 15 harbors, 19 fishing ports.
Flights from Tokyo take 30 minutes, while boats take 7–10 hours and jetfoils make the route in about two hours. Transportation on the islands is considered important to the quality of life, why about 215 km of paved main roads serve a kind of vehicles. There was no electricity on the islands before 1953, but by 1962, 98% of the area receives electricity; the islands occupy the northern portion of the Izu-Bonin-Mariana Arc which extends to the Izu Peninsula and Mount Fuji on the Honshū mainland which are northern extensions of the Izu volcanic arc. The Izu arc ends there at a tectonic triple junction. Volcanic activity is frequent in the area. 31 people were killed when the research vessel Kaiyō Maru no 5 was destroyed during the 1953 eruption of Myōjin-shō. Volcanic activity, including the release of harmful gases, forced the evacuation of Miyake-jima in 2000. Residents were allowed to return permanently to the island in February 2005 but were required to carry gas masks in case of future volcanic emissions.
To handle the various types of natural disasters threatening the region, including tsunamis, storm and volcanism, Tokyo metropolitan government has developed prevention and safety measures, including hazard maps and evacuation guidance, signs, a transport system for emergency supplies. A chain of volcanic islands, the Izu Archipelago are oceanic islands that formed recently without any previous connection to mainland Japan. In contrast to isolated Pacific islands, such as Hawaii and the Galápagos, the Izu Islands are located near the mainland and have thus been colonized by various species by overseas dispersal from the mainland or from adjacent islands; this make them interesting for the studies of evolutionary processes. Campanula colonized the entire archipelago in a single event; the Euhadra snails, endemic to Japan, populated the islands in a single event and all ind
An island or isle is any piece of sub-continental land, surrounded by water. Small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or a lake island may be called an eyot or ait, a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, such as the Philippines. An island may be described despite the presence of an artificial land bridge; some places may retain "island" in their names for historical reasons after being connected to a larger landmass by a land bridge or landfill, such as Coney Island and Coronado Island, though these are speaking, tied islands. Conversely, when a piece of land is separated from the mainland by a man-made canal, for example the Peloponnese by the Corinth Canal or Marble Hill in northern Manhattan during the time between the building of the United States Ship Canal and the filling-in of the Harlem River which surrounded the area, it is not considered an island.
There are two main types of islands in the sea: oceanic. There are artificial islands; the word island derives from Middle English iland, from Old English igland. However, the spelling of the word was modified in the 15th century because of a false etymology caused by an incorrect association with the etymologically unrelated Old French loanword isle, which itself comes from the Latin word insula. Old English ieg is a cognate of Swedish ö and German Aue, related to Latin aqua. Greenland is the world's largest island, with an area of over 2.1 million km2, while Australia, the world's smallest continent, has an area of 7.6 million km2, but there is no standard of size that distinguishes islands from continents, or from islets. There is a difference between continents in terms of geology. Continents are the largest landmass of a particular continental plate. By contrast, islands are either extensions of the oceanic crust, or belong to a continental plate containing a larger landmass. Continental islands are bodies of land.
Examples are Borneo, Sumatra, Sakhalin and Hainan off Asia. A special type of continental island is the microcontinental island, created when a continent is rifted. Examples are Madagascar and Socotra off Africa, New Caledonia, New Zealand, some of the Seychelles. Another subtype is an island or bar formed by deposition of tiny rocks where water current loses some of its carrying capacity; this includes: barrier islands, which are accumulations of sand deposited by sea currents on the continental shelves fluvial or alluvial islands formed in river deltas or midstream within large rivers. While some are transitory and may disappear if the volume or speed of the current changes, others are stable and long-lived. Islets are small islands. Oceanic islands are islands; the vast majority are volcanic in origin, such as Saint Helena in the South Atlantic Ocean. The few oceanic islands that are not volcanic are tectonic in origin and arise where plate movements have lifted up the ocean floor above the surface.
Examples are Saint Paul Rocks in the Atlantic Ocean and Macquarie Island in the Pacific. One type of volcanic oceanic island is found in a volcanic island arc; these islands arise from volcanoes. Examples are the Aleutian Islands, the Mariana Islands, most of Tonga in the Pacific Ocean; the only examples in the Atlantic Ocean are some of the Lesser Antilles and the South Sandwich Islands. Another type of volcanic oceanic island occurs. There are two examples: Iceland, the world's second largest volcanic island, Jan Mayen. Both are in the Atlantic. A third type of volcanic oceanic island is formed over volcanic hotspots. A hotspot is more or less stationary relative to the moving tectonic plate above it, so a chain of islands results as the plate drifts. Over long periods of time, this type of island is "drowned" by isostatic adjustment and eroded, becoming a seamount. Plate movement across a hot-spot produces a line of islands oriented in the direction of the plate movement. An example is the Hawaiian Islands, from Hawaii to Kure, which continue beneath the sea surface in a more northerly direction as the Emperor Seamounts.
Another chain with similar orientation is the Tuamotu Archipelago. The southernmost chain is the Austral Islands, with its northerly trending part the atolls in the nation of Tuvalu. Tristan da Cunha is an example of a hotspot volcano in the Atlantic Ocean. Another hotspot in the Atlantic is the island of Surtsey, formed in 1963. An atoll is an island formed from a coral reef that has grown on an eroded and submerged volcanic island; the reef forms a new island. Atolls are ring-shaped with a central lagoon. Examples are the Line Islands
Global Volcanism Program
The Smithsonian Institution's Global Volcanism Program documents Earth's volcanoes and their eruptive history over the past 10,000 years. The GVP reports on current eruptions from around the world as well as maintaining a database repository on active volcanoes and their eruptions. In this way, a global context for the planet's active volcanism is presented. Smithsonian reporting on current volcanic activity dates back to 1968, with the Center for Short-Lived Phenomena; the GVP is housed in the Department of Mineral Sciences, part of the National Museum of Natural History, on the National Mall in Washington, D. C. During the early stages of an eruption, the GVP acts as a clearing house of reports and imagery which are accumulated from a global network of contributors; the early flow of information is managed such that the right people are contacted as well as helping to sort out vague and contradictory aspects that arise during the early days of an eruption. The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the United States Geological Survey's Volcano Hazards Program.
Notices of volcanic activity posted on the report website are preliminary and subject to change as events are studied in more detail. Detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism NetworkThe GVP documents the last 10,000 years of Earth's volcanism; the historic activity can guide perspectives on possible future events and on volcanoes showing activity. GVP's volcano and eruption databases constitute a foundation for all statistical statements concerning locations and magnitudes of Earth's volcanic eruptions during the past recent 10,000 years. Two editions of Volcanoes of the World, a regional directory... and were published based on the GVP data and interpretations. Prediction of volcanic activity Timeline of volcanism on Earth Volcanic explosivity index Volcano Number Global Volcanism Program Global Volcanism Program Facebook page
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are found where tectonic plates are diverging or converging, most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can form where there is stretching and thinning of the crust's plates, e.g. in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has been explained as mantle plumes; these so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.
Volcanoes are not created where two tectonic plates slide past one another. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere. Volcanic winters have caused catastrophic famines; the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is sometimes spelled vulcanology. At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock; because the crust is thin at these ridges due to the pull of the tectonic plates, the release of pressure leads to adiabatic expansion and the partial melting of the mantle, causing volcanism and creating new oceanic crust.
Most divergent plate boundaries are at the bottom of the oceans. Black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed. Subduction zones are places where two plates an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges, under the continental plate, forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma; this magma tends to be viscous because of its high silica content, so it does not attain the surface but cools and solidifies at depth. When it does reach the surface, however, a volcano is formed. Typical examples are the volcanoes in the Pacific Ring of Fire. Hotspots are volcanic areas believed to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting.
Because tectonic plates move across them, each volcano becomes dormant and is re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; this theory, has been doubted. The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; the features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material and gases can develop anywhere on the landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea. Other types of volcano include cryovolcanoes on some moons of Jupiter and Neptune. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is a vent of an igneous volcano.
Volcanic fissure vents are linear fractures through which lava emerges. Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent, they do not explode catastrophically. Since low-viscosity magma is low in silica, shield volcanoes are more common in oceanic than continental settings; the Hawaiian volcanic chain is a series of shield cones, they are common in Iceland, as well. Lava domes are built by slow eruptions of viscous lava, they are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helen
Marine habitats are habitats that support marine life. Marine life depends in some way on the saltwater, in the sea. A habitat is an environmental area inhabited by one or more living species; the marine environment supports many kinds of these habitats. Marine habitats can be divided into open ocean habitats. Coastal habitats are found in the area that extends from as far as the tide comes in on the shoreline out to the edge of the continental shelf. Most marine life is found in coastal habitats though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into demersal zones. Pelagic habitats are found near the surface or in the open water column, away from the bottom of the ocean. Demersal habitats are on the bottom of the ocean. An organism living in a pelagic habitat is said to be a pelagic organism, as in pelagic fish. An organism living in a demersal habitat is said to be a demersal organism, as in demersal fish.
Pelagic habitats are intrinsically shifting and ephemeral, depending on what ocean currents are doing. Marine habitats can be modified by their inhabitants; some marine organisms, like corals, kelp and seagrasses, are ecosystem engineers which reshape the marine environment to the point where they create further habitat for other organisms. By volume, oceans provide about 99 percent of the living space on the planet. In contrast to terrestrial habitats, marine habitats are ephemeral. Swimming organisms find areas by the edge of a continental shelf a good habitat, but only while upwellings bring nutrient rich water to the surface. Shellfish find habitat on sandy beaches, but storms and currents mean their habitat continually reinvents itself; the presence of seawater is common to all marine habitats. Beyond that many other things determine whether a marine area makes a good habitat and the type of habitat it makes. For example: temperature – is affected by geographical latitude, ocean currents, the discharge of rivers, by the presence of hydrothermal vents or cold seeps sunlight – photosynthetic processes depend on how deep and turbid the water is nutrients – are transported by ocean currents to different marine habitats from land runoff, or by upwellings from the deep sea, or they sink through the sea as marine snow salinity – varies in estuaries or near river deltas, or by hydrothermal vents dissolved gases – oxygen levels in particular, can be increased by wave actions and decreased during algal blooms acidity – this is to do with dissolved gases above, since the acidity of the ocean is controlled by how much carbon dioxide is in the water.
Turbulence – ocean waves, fast currents and the agitation of water affect the nature of habitats cover – the availability of cover such as the adjacency of the sea bottom, or the presence of floating objects the occupying organisms themselves – since organisms modify their habitats by the act of occupying them, some, like corals, kelp and seagrasses, create further habitats for other organisms. There are five major oceans. Coastlines fringe the land for nearly 380,000 kilometres. Altogether, the ocean occupies 71 percent of the world surface, averaging nearly four kilometres in depth. By volume, the ocean provides about 99 percent of the living space on the planet; the science fiction writer Arthur C. Clarke has pointed out it would be more appropriate to refer to the planet Earth as the planet Sea or the planet Ocean. Marine habitats can be broadly divided into demersal habitats. Pelagic habitats are the habitats of the open water column, away from the bottom of the ocean. Demersal habitats are the habitats that are on the bottom of the ocean.
An organism living in a pelagic habitat is said to be a pelagic organism, as in pelagic fish. An organism living in a demersal habitat is said to be a demersal organism, as in demersal fish. Pelagic habitats are intrinsically ephemeral, depending on; the land-based ecosystem depends on topsoil and fresh water, while the marine ecosystem depends on dissolved nutrients washed down from the land. Ocean deoxygenation poses a threat to marine habitats, due to the growth of low oxygen zones. In marine systems, ocean currents have a key role determining which areas are effective as habitats, since ocean currents transport the basic nutrients needed to support marine life. Plankton are the life forms that inhabit the ocean that are so small that they cannot propel themselves through the water, but must drift instead with the currents. If the current carries the right nutrients, if it flows at a suitably shallow depth where there is plenty of sunlight such a current itself can become a suitable habitat for photosynthesizing tiny algae called phytoplankton.
These tiny plants are the primary producers in the ocean, at the start of the food chain. In turn, as the population of drifting phytoplankton grows, the water becomes a suitable habitat for zooplankton, which feed on the phytoplankton. While phytoplankton are tiny drifting plants, zooplankton are tiny drifting animals, such as the larvae of fish and marine invertebrates. If sufficient zooplankton establish themselves, the current becomes a candidate habitat for the forage fish that feed on them, and if sufficient forage fish move to the area, it becomes a candidate habitat for larger predatory fish and other marine animals that feed on the forage fish. In this dynamic way, the current itself can, over tim