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Pacific Ocean

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Earth's five oceans
     * Atlantic Ocean
     * Arctic Ocean
     * Indian Ocean
     * Pacific Ocean
     * Southern Ocean

   The Pacific Ocean (from the Latin name Mare Pacificum, "peaceful sea",
   bestowed upon it by the Portuguese explorer Ferdinand Magellan) is the
   world's largest body of water.

Overview

   The ocean encompasses a third of the Earth's surface, having an area of
   179.7 million square kilometres (69.4 million sq mi and 161 million
   cubic mi) —significantly larger than Earth's entire landmass, with room
   for another Africa to spare. Extending approximately 15,500 kilometres
   (9,600  mi) from the Bering Sea in the Arctic to the icy margins of
   Antarctica's Ross Sea in the south (although the Antarctic regions of
   the Pacific are sometimes described as part of the circumpolar Southern
   Ocean), the Pacific reaches its greatest east-west width at about 5°N
   latitude, where it stretches approximately 19,800 kilometres (12,300
   mi) from Indonesia to the coast of Colombia and Peru. The western limit
   of the ocean is often placed at the Strait of Malacca. The lowest point
   on earth—the Mariana Trench—lies 10,911 metres (35,797 ft) below sea
   level. Its average depth is 4,300 metres (14,000 ft).
   The shoreline at Palm Beach, New South Wales
   Enlarge
   The shoreline at Palm Beach, New South Wales

   The Pacific contains about 25,000 islands (more than the total number
   in the rest of the world's oceans combined), the majority of which are
   found south of the equator.

   The Pacific Ocean is currently shrinking from plate tectonics, while
   the Atlantic Ocean is increasing in size.

   Along the Pacific Ocean's irregular western margins lie many seas, the
   largest of which are the Celebes Sea, Coral Sea, East China Sea,
   Philippine Sea, Sea of Japan, South China Sea, Sulu Sea, Tasman Sea,
   and Yellow Sea. The Strait of Malacca joins the Pacific and the Indian
   Oceans on the west, and the Strait of Magellan links the Pacific with
   the Atlantic Ocean on the east. To the north, the Bering Strait
   connects the Pacific with the Arctic Ocean.

   As the Pacific straddles the ± 180° meridian, the West Pacific (or
   western Pacific, near Asia) is actually in the Eastern Hemisphere,
   while the East Pacific (or eastern Pacific, near the Americas) is
   actually in the Western Hemisphere.
   Coastal area of Viña del Mar, Chile
   Enlarge
   Coastal area of Viña del Mar, Chile

   For most of Magellan's voyage from the Strait of Magellan to the
   Philippines, the explorer indeed found the ocean peaceful. However, the
   Pacific is not always peaceful. Many tropical cyclones ( typhoons, the
   equivalent of Atlantic hurricanes), batter the islands of the Pacific.
   The lands around the Pacific rim are full of volcanoes and often
   affected by earthquakes. Tsunamis, caused by underwater earthquakes,
   have devastated many islands and destroyed entire towns.

   Pacific Ocean

Water characteristics

   Water temperatures in the Pacific vary from freezing in the poleward
   areas to about 25-30 ° Celsius (84 ° F) near the equator. Salinity also
   varies latitudinally. Water near the equator is less salty than that
   found in the mid-latitudes because of abundant equatorial precipitation
   throughout the year. Poleward of the temperate latitudes salinity is
   also low, because little evaporation of seawater takes place in these
   frigid areas. The Pacific ocean is generally warmer than the Atlantic
   ocean.

   The surface circulation of Pacific waters is generally clockwise in the
   Northern Hemisphere (the North Pacific Gyre) and counter-clockwise in
   the Southern Hemisphere. The North Equatorial Current, driven westward
   along latitude 15°N by the trade winds, turns north near the
   Philippines to become the warm Japan or Kuroshio Current.

   Turning eastward at about 45°N, the Kuroshio forks and some waters move
   northward as the Aleutian Current, while the rest turn southward to
   rejoin the North Equatorial Current. The Aleutian Current branches as
   it approaches North America and forms the base of a counter-clockwise
   circulation in the Bering Sea. Its southern arm becomes the chilled
   slow, south-flowing California Current.

   The South Equatorial Current, flowing west along the equator, swings
   southward east of New Guinea, turns east at about 50°S, and joins the
   main westerly circulation of the Southern Pacific, which includes the
   Earth-circling Antarctic Circumpolar Current. As it approaches the
   Chilean coast, the South Equatorial Current divides; one branch flows
   around Cape Horn and the other turns north to form the Peru or Humboldt
   Current.
   View of the Pacific Ocean from Pebble Beach, California.
   Enlarge
   View of the Pacific Ocean from Pebble Beach, California.

Geology

   The Andesite Line is the most significant regional distinction in the
   Pacific. It separates the deeper, alkaline igneous rock of the Central
   Pacific Basin from the partially submerged continental areas of acidic
   igneous rock on its margins. The Andesite Line follows the western edge
   of the islands off California and passes south of the Aleutian arc,
   along the eastern edge of the Kamchatka Peninsula, the Kuril Islands,
   Japan, the Mariana Islands, the Solomon Islands, and New Zealand. The
   dissimilarity continues northeastward along the western edge of the
   Albatross Cordillera along South America to Mexico, returning then to
   the islands off California. Indonesia, the Philippines, Japan, New
   Guinea, and New Zealand—all eastward extensions of the continental
   blocks of Australia and Asia—lie outside the Andesite Line.

   Within the closed loop of the Andesite Line are most of the deep
   troughs, submerged volcanic mountains, and oceanic volcanic islands
   that characterize the Central Pacific Basin. Here basaltic lavas gently
   flow out of rifts to build huge dome-shaped volcanic mountains whose
   eroded summits form island arcs, chains, and clusters. Outside the
   Andesite Line, volcanism is of the explosive type, and the Pacific Ring
   of Fire is the world's foremost belt explosive volcanism.

Landmasses

   The Pacific is ringed by many volcanoes and oceanic trenches
   Enlarge
   The Pacific is ringed by many volcanoes and oceanic trenches

   The largest landmass entirely within the Pacific Ocean is the island of
   New Guinea— the second largest island in the world. Almost all of the
   smaller islands of the Pacific lie between 30°N and 30°S, extending
   from South-east Asia to Easter Island; the rest of the Pacific Basin is
   almost entirely submerged.

   The great triangle of Polynesia, connecting Hawaii, Easter Island, and
   New Zealand, encompasses the island arcs and clusters of the Cook
   Islands, Marquesas, Samoa, Society, Tokelau, Tonga, Tuamotu, Tuvalu &
   Wallis and Futuna islands.

   North of the equator and west of the International Date Line are the
   numerous small islands of Micronesia, including the Caroline Islands,
   the Marshall Islands, and the Mariana Islands.

   In the southwestern corner of the Pacific lie the islands of Melanesia,
   dominated by New Guinea. Other important island groups of Melanesia
   include the Bismarck Archipelago, Fiji, New Caledonia, the Solomon
   Islands, and Vanuatu.

   Islands in the Pacific Ocean are of four basic types: continental
   islands, high islands, coral reefs, and uplifted coral platforms.
   Continental islands lie outside the Andesite Line and include New
   Guinea, the islands of New Zealand, and the Philippines. These islands
   are structurally associated with nearby continents. High islands are of
   volcanic origin, and many contain active volcanoes. Among these are
   Bougainville, Hawaii, & the Solomon Islands.

   The third and fourth types of islands are both the result of coralline
   island building. Coral reefs are low-lying structures that have built
   up on basaltic lava flows under the ocean's surface. One of the most
   dramatic is the Great Barrier Reef off northeastern Australia. A second
   island type formed of coral is the uplifted coral platform, which is
   usually slightly larger than the low coral islands. Examples include
   Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of
   French Polynesia.

History and economy

   Important human migrations occurred in the Pacific in prehistoric
   times, most notably those of the Austronesians (specifically, the
   Polynesians) from the Asian edge of the ocean to Tahiti and then to
   Hawaii and New Zealand, and much later, to Easter Island.

   The ocean was sighted by Europeans early in the 16th century, first by
   Vasco Núñez de Balboa ( 1513), who crossed the Isthmus of Panama, and
   then by Ferdinand Magellan, who sailed the Pacific during his
   circumnavigation ( 1519- 1522). In 1564, conquistadors crossed the
   ocean from Mexico led by Miguel López de Legazpi who sailed to the
   Philippines and Mariana Islands. For the remainder of the 16th century,
   Spanish influence was paramount, with ships sailing from Spain to the
   Philippines, New Guinea, and the Solomon Islands; the Manila Galleons
   linked Manila and Acapulco. In 16th century also the Ragusean galleys
   of Dubrovnik led by Vice Bune explored southwestern Pacific, and
   discovered the islands of Bismarck Archipelago, Vanuatu (New Hebrides),
   etc.

   During the 17th century, the Dutch, sailing around southern Africa,
   dominated discovery and trade; Abel Janszoon Tasman discovered Tasmania
   and New Zealand in 1642; in that century Ragusean traders prevailed in
   Melanesia. The 18th century marked a burst of exploration by the
   Russians in Alaska and the Aleutian Islands, the French in Polynesia,
   and the British in the three voyages of James Cook (to the South
   Pacific and Australia, Hawaii, and the North American Pacific
   Northwest).

   Growing imperialism during the 19th century resulted in the occupation
   of much of Oceania by Great Britain and France, followed by the United
   States. Significant contributions to oceanographic knowledge were made
   by the voyages of the HMS Beagle in the 1830s, with Charles Darwin
   aboard; the HMS Challenger during the 1870s; the USS Tuscarora
   (1873-76); and the German Gazelle (1874-76). Although the United States
   conquered the Philippines in 1898, Japan controlled the western Pacific
   by 1914 and occupied many other islands during World War II. By the end
   of the war, the U.S. Pacific Fleet was the virtual master of the ocean.

   Seventeen independent states are located in the Pacific: Australia,
   Fiji, Japan, Kiribati, Marshall Islands, Micronesia, Nauru, New
   Zealand, Palau, Papua New Guinea, the Philippines, Samoa, Solomon
   Islands, Republic of China (Taiwan), Tonga, Tuvalu, and Vanuatu. Eleven
   of these nations have achieved full independence since 1960. The
   Northern Mariana Islands are self-governing with external affairs
   handled by the United States, and Cook Islands and Niue are in similar
   relationships with New Zealand. Also within the Pacific is the U.S.
   state of Hawaii and several island territories and possessions of
   Australia, Chile, Ecuador, France, Japan, New Zealand, the United
   Kingdom, and the United States.

   The exploitation of the Pacific's mineral wealth is hampered by the
   ocean's great depths. In shallow waters of the continental shelves off
   the coasts of Australia and New Zealand, petroleum and natural gas are
   extracted, and pearls are harvested along the coasts of Australia,
   Japan, Papua New Guinea, Nicaragua, Panama, and the Philippines,
   although in sharply declining volume in some cases. The Pacific's
   greatest asset is its fish. The shoreline waters of the continents and
   the more temperate islands yield herring, salmon, sardines, snapper,
   swordfish, and tuna, as well as shellfish.

   In 1986, the member nations of the South Pacific Forum declared the
   area a nuclear-free zone in an effort to halt nuclear testing and
   prevent the dumping of nuclear waste there.

Major ports and harbours

     * Acapulco, Mexico
     * Anchorage, Alaska, United States
     * Antofagasta, Chile
     * Arica, Chile
     * Auckland, New Zealand
     * Bangkok, Thailand
     * Brisbane, Queensland, Australia
     * Buenaventura, Colombia
     * Busan, Korea
     * Callao, Peru
     * Cebu City, Philippines
     * Dalian, People's Republic of China
     * Ensenada, Mexico
     * Guayaquil, Ecuador
     * Hong Kong, People's Republic of China
     * Honolulu, Hawaii, United States
     * Iquique, Chile
     * Kaohsiung, Taiwan, Republic of China
     * Kitimat, British Columbia, Canada
     * Keelung, Taiwan
     * Kobe, Japan
     * Laem Chabang, Thailand
     * Long Beach, California, United States
     * Los Angeles, California, United States

     * Melbourne, Victoria, Australia
     * Metro Manila, Philippines
     * Oakland, California, United States
     * Panama City, Panama
     * Portland, Oregon, United States
     * Prince Rupert, British Columbia, Canada
     * Puerto Montt, Chile
     * Qingdao, People's Republic of China
     * San Antonio,Chile
     * San Diego, California, United States
     * San Francisco, California, United States
     * Sapporo, Japan
     * Seattle, Washington, United States
     * Shanghai, People's Republic of China
     * Shenzhen, People's Republic of China
     * Singapore
     * Songkhla, Thailand
     * Sydney, New South Wales, Australia
     * Taichung, Taiwan, Republic of China
     * Talcahuano, Chile
     * Tianjin, People's Republic of China
     * Tijuana, Mexico
     * Valparaiso, Chile
     * Vancouver, British Columbia, Canada
     * Victoria, British Columbia, Canada
     * Vladivostok, Russia
     * Xiamen, People's Republic of China
     * Yantai, People's Republic of China
     * Yokohama, Japan

   Retrieved from " http://en.wikipedia.org/wiki/Pacific_Ocean"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
