Pacific Ocean

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"North Pacific", "Pacific", and "Pacific region" redirect here. Pacific Ocean_sentence_0

For the region in Colombia, see Pacific Region, Colombia. Pacific Ocean_sentence_1

For other uses, see North Pacific (disambiguation) and Pacific (disambiguation). Pacific Ocean_sentence_2

Pacific Ocean_table_infobox_0

Pacific OceanPacific Ocean_header_cell_0_0_0
CoordinatesPacific Ocean_header_cell_0_1_0 Pacific Ocean_cell_0_1_1
Surface areaPacific Ocean_header_cell_0_3_0 165,250,000 km (63,800,000 sq mi)Pacific Ocean_cell_0_3_1
Average depthPacific Ocean_header_cell_0_4_0 4,280 m (14,040 ft)Pacific Ocean_cell_0_4_1
Max. depthPacific Ocean_header_cell_0_5_0 10,911 m (35,797 ft)Pacific Ocean_cell_0_5_1
Water volumePacific Ocean_header_cell_0_6_0 710,000,000 km (170,000,000 cu mi)Pacific Ocean_cell_0_6_1
IslandsPacific Ocean_header_cell_0_8_0 List of islandsPacific Ocean_cell_0_8_1
SettlementsPacific Ocean_header_cell_0_9_0 Anchorage, Auckland, Brisbane, Busan, Buenaventura, Guayaquil, Hong Kong, Honolulu, Lima, Los Angeles, Magadan, Manila, Melbourne, Osaka, Panama City, Papeete, San Francisco Bay Area, San Diego, Seattle, Shanghai, Singapore, Suva, Sydney, Tijuana, Tokyo, Valparaíso, Vancouver, Vladivostok, Christchurch,Pacific Ocean_cell_0_9_1

The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. Pacific Ocean_sentence_3

It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. Pacific Ocean_sentence_4

At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with an Antarctic southern border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, making it larger than all of Earth's land area combined (148,000,000 square kilometers). Pacific Ocean_sentence_5

The centers of both the Water Hemisphere and the Western Hemisphere are in the Pacific Ocean. Pacific Ocean_sentence_6

Ocean circulation (caused by the Coriolis effect) subdivides it into two largely independent volumes of water, which meet at the equator: the North(ern) Pacific Ocean and South(ern) Pacific Ocean. Pacific Ocean_sentence_7

The Galápagos and Gilbert Islands, while straddling the equator, are deemed wholly within the South Pacific. Pacific Ocean_sentence_8

Its mean depth is 4,000 meters (13,000 feet). Pacific Ocean_sentence_9

Challenger Deep in the Mariana Trench, located in the western north Pacific, is the deepest point in the world, reaching a depth of 10,928 meters (35,853 feet). Pacific Ocean_sentence_10

The Pacific also contains the deepest point in the Southern Hemisphere, the Horizon Deep in the Tonga Trench, at 10,823 meters (35,509 feet). Pacific Ocean_sentence_11

The third deepest point on Earth, the Sirena Deep, is also located in the Mariana Trench. Pacific Ocean_sentence_12

The western Pacific has many major marginal seas, including the South China Sea, the East China Sea, the Sea of Japan, the Sea of Okhotsk, the Philippine Sea, the Coral Sea, and the Tasman Sea. Pacific Ocean_sentence_13

Etymology Pacific Ocean_section_0

Though the peoples of Asia and Oceania have traveled the Pacific Ocean since prehistoric times, the eastern Pacific was first sighted by Europeans in the early 16th century when Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and discovered the great "southern sea" which he named Mar del Sur (in Spanish). Pacific Ocean_sentence_14

The ocean's current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favorable winds on reaching the ocean. Pacific Ocean_sentence_15

He called it Mar Pacífico, which in both Portuguese and Spanish means "peaceful sea". Pacific Ocean_sentence_16

Biggest seas in Pacific Ocean Pacific Ocean_section_1

Top large seas: Pacific Ocean_sentence_17

History Pacific Ocean_section_2

Early migrations Pacific Ocean_section_3

Important human migrations occurred in the Pacific in prehistoric times. Pacific Ocean_sentence_18

About 3000 BC, the Austronesian peoples on the island of Taiwan mastered the art of long-distance canoe travel and spread themselves and their languages south to the Philippines, Indonesia, and maritime Southeast Asia; west towards Madagascar; southeast towards New Guinea and Melanesia (intermarrying with native Papuans); and east to the islands of Micronesia, Oceania and Polynesia. Pacific Ocean_sentence_19

Long-distance trade developed all along the coast from Mozambique to Japan. Pacific Ocean_sentence_20

Trade, and therefore knowledge, extended to the Indonesian islands but apparently not Australia. Pacific Ocean_sentence_21

In 219 BC Xu Fu sailed out into the Pacific searching for the elixir of immortality. Pacific Ocean_sentence_22

By at least 878 when there was a significant Islamic settlement in Canton much of this trade was controlled by Arabs or Muslims. Pacific Ocean_sentence_23

From 1404 to 1433 Zheng He led expeditions into the Indian Ocean. Pacific Ocean_sentence_24

European exploration Pacific Ocean_section_4

Main article: Exploration of the Pacific Pacific Ocean_sentence_25

The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of António de Abreu and Francisco Serrão, via the Lesser Sunda Islands, to the Maluku Islands, in 1512, and with Jorge Álvares's expedition to southern China in 1513, both ordered by Afonso de Albuquerque from Malacca. Pacific Ocean_sentence_26

The eastern side of the ocean was discovered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and reached a new ocean. Pacific Ocean_sentence_27

He named it Mar del Sur (literally, "Sea of the South" or "South Sea") because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. Pacific Ocean_sentence_28

In 1520, navigator Ferdinand Magellan and his crew were the first to cross the Pacific in recorded history. Pacific Ocean_sentence_29

They were part of a Spanish expedition to the Spice Islands that would eventually result in the first world circumnavigation. Pacific Ocean_sentence_30

Magellan called the ocean Pacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off Cape Horn, the expedition found calm waters. Pacific Ocean_sentence_31

The ocean was often called the Sea of Magellan in his honor until the eighteenth century. Pacific Ocean_sentence_32

Magellan stopped at one uninhabited Pacific island before stopping at Guam in March 1521. Pacific Ocean_sentence_33

Although Magellan himself died in the Philippines in 1521, Spanish navigator Juan Sebastián Elcano led the remains of the expedition back to Spain across the Indian Ocean and round the Cape of Good Hope, completing the first world circumnavigation in 1522. Pacific Ocean_sentence_34

Sailing around and east of the Moluccas, between 1525 and 1527, Portuguese expeditions discovered the Caroline Islands, the Aru Islands, and Papua New Guinea. Pacific Ocean_sentence_35

In 1542–43 the Portuguese also reached Japan. Pacific Ocean_sentence_36

In 1564, five Spanish ships carrying 379 explorers crossed the ocean from Mexico led by Miguel López de Legazpi, and sailed to the Philippines and Mariana Islands. Pacific Ocean_sentence_37

For the remainder of the 16th century, Spanish influence was paramount, with ships sailing from Mexico and Peru across the Pacific Ocean to the Philippines via Guam, and establishing the Spanish East Indies. Pacific Ocean_sentence_38

The Manila galleons operated for two and a half centuries, linking Manila and Acapulco, in one of the longest trade routes in history. Pacific Ocean_sentence_39

Spanish expeditions also discovered Tuvalu, the Marquesas, the Cook Islands, the Solomon Islands, and the Admiralty Islands in the South Pacific. Pacific Ocean_sentence_40

Later, in the quest for Terra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator Pedro Fernandes de Queirós, discovered the Pitcairn and Vanuatu archipelagos, and sailed the Torres Strait between Australia and New Guinea, named after navigator Luís Vaz de Torres. Pacific Ocean_sentence_41

Dutch explorers, sailing around southern Africa, also engaged in discovery and trade; Willem Janszoon, made the first completely documented European landing in Australia (1606), in Cape York Peninsula, and Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and discovered Tasmania and New Zealand in 1642. Pacific Ocean_sentence_42

In the 16th and 17th centuries, Spain considered the Pacific Ocean a mare clausum—a sea closed to other naval powers. Pacific Ocean_sentence_43

As the only known entrance from the Atlantic, the Strait of Magellan was at times patrolled by fleets sent to prevent entrance of non-Spanish ships. Pacific Ocean_sentence_44

On the western side of the Pacific Ocean the Dutch threatened the Spanish Philippines. Pacific Ocean_sentence_45

The 18th century marked the beginning of major exploration by the Russians in Alaska and the Aleutian Islands, such as the First Kamchatka expedition and the Great Northern Expedition, led by the Danish Russian navy officer Vitus Bering. Pacific Ocean_sentence_46

Spain also sent expeditions to the Pacific Northwest, reaching Vancouver Island in southern Canada, and Alaska. Pacific Ocean_sentence_47

The French explored and settled Polynesia, and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii, and the North American Pacific Northwest. Pacific Ocean_sentence_48

In 1768, Pierre-Antoine Véron, a young astronomer accompanying Louis Antoine de Bougainville on his voyage of exploration, established the width of the Pacific with precision for the first time in history. Pacific Ocean_sentence_49

One of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. Pacific Ocean_sentence_50

It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Pacific Ocean_sentence_51

New Imperialism Pacific Ocean_section_5

See also: New Imperialism Pacific Ocean_sentence_52

Growing imperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and the United States. Pacific Ocean_sentence_53

Significant contributions to oceanographic knowledge were made by the voyages of HMS Beagle in the 1830s, with Charles Darwin aboard; HMS Challenger during the 1870s; the USS Tuscarora (1873–76); and the German Gazelle (1874–76). Pacific Ocean_sentence_54

In Oceania, France obtained a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853, respectively. Pacific Ocean_sentence_55

After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro negotiated the incorporation of the island into Chile with native Rapanui in 1888. Pacific Ocean_sentence_56

By occupying Easter Island, Chile joined the imperial nations. Pacific Ocean_sentence_57

By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile. Pacific Ocean_sentence_58

Although the United States gained control of Guam and the Philippines from Spain in 1898, Japan controlled most of the western Pacific by 1914 and occupied many other islands during the Pacific War; however, by the end of that war, Japan was defeated and the U.S. Pacific Ocean_sentence_59 Pacific Fleet was the virtual master of the ocean. Pacific Ocean_sentence_60

The Japanese-ruled Northern Mariana Islands came under the control of the United States. Pacific Ocean_sentence_61

Since the end of World War II, many former colonies in the Pacific have become independent states. Pacific Ocean_sentence_62

Geography Pacific Ocean_section_6

The Pacific separates Asia and Australia from the Americas. Pacific Ocean_sentence_63

It may be further subdivided by the equator into northern (North Pacific) and southern (South Pacific) portions. Pacific Ocean_sentence_64

It extends from the Antarctic region in the South to the Arctic in the north. Pacific Ocean_sentence_65

The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km (63,800,000 sq mi)— larger than Earth's entire landmass combined, 150,000,000 km (58,000,000 sq mi). Pacific Ocean_sentence_66

Extending approximately 15,500 km (9,600 mi) from the Bering Sea in the Arctic to the northern extent of the circumpolar Southern Ocean at 60°S (older definitions extend it to Antarctica's Ross Sea), the Pacific reaches its greatest east–west width at about 5°N latitude, where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast of Colombia—halfway around the world, and more than five times the diameter of the Moon. Pacific Ocean_sentence_67

The lowest known point on Earth—the Mariana Trench—lies 10,911 m (35,797 ft; 5,966 fathoms) below sea level. Pacific Ocean_sentence_68

Its average depth is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km (170,000,000 cu mi). Pacific Ocean_sentence_69

Due to the effects of plate tectonics, the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km (0.20 sq mi) a year. Pacific Ocean_sentence_70

By contrast, the Atlantic Ocean is increasing in size. Pacific Ocean_sentence_71

Along the Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea, Coral Sea, East China Sea (East Sea), Philippine Sea, Sea of Japan, South China Sea (South Sea), Sulu Sea, Tasman Sea, and Yellow Sea (West Sea of Korea). Pacific Ocean_sentence_72

The Indonesian Seaway (including the Strait of Malacca and Torres Strait) joins the Pacific and the Indian Ocean to the west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. Pacific Ocean_sentence_73

To the north, the Bering Strait connects the Pacific with the Arctic Ocean. Pacific Ocean_sentence_74

As the Pacific straddles the 180th meridian, the West Pacific (or western Pacific, near Asia) is in the Eastern Hemisphere, while the East Pacific (or eastern Pacific, near the Americas) is in the Western Hemisphere. Pacific Ocean_sentence_75

The Southern Pacific Ocean harbors the Southeast Indian Ridge crossing from south of Australia turning into the Pacific-Antarctic Ridge (north of the South Pole) and merges with another ridge (south of South America) to form the East Pacific Rise which also connects with another ridge (south of North America) which overlooks the Juan de Fuca Ridge. Pacific Ocean_sentence_76

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. Pacific Ocean_sentence_77

Many tropical storms batter the islands of the Pacific. Pacific Ocean_sentence_78

The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes. Pacific Ocean_sentence_79

Tsunamis, caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns. Pacific Ocean_sentence_80

The Martin Waldseemüller map of 1507 was the first to show the Americas separating two distinct oceans. Pacific Ocean_sentence_81

Later, the Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size. Pacific Ocean_sentence_82

Bordering countries and territories Pacific Ocean_section_7

Sovereign nations Pacific Ocean_section_8

Territories Pacific Ocean_section_9

Landmasses and islands Pacific Ocean_section_10

Main article: Pacific Islands Pacific Ocean_sentence_83

The Pacific Ocean has most of the islands in the world. Pacific Ocean_sentence_84

There are about 25,000 islands in the Pacific Ocean. Pacific Ocean_sentence_85

The islands entirely within the Pacific Ocean can be divided into three main groups known as Micronesia, Melanesia and Polynesia. Pacific Ocean_sentence_86

Micronesia, which lies north of the equator and west of the International Date Line, includes the Mariana Islands in the northwest, the Caroline Islands in the center, the Marshall Islands to the east and the islands of Kiribati in the southeast. Pacific Ocean_sentence_87

Melanesia, to the southwest, includes New Guinea, the world's second largest island after Greenland and by far the largest of the Pacific islands. Pacific Ocean_sentence_88

The other main Melanesian groups from north to south are the Bismarck Archipelago, the Solomon Islands, Santa Cruz, Vanuatu, Fiji and New Caledonia. Pacific Ocean_sentence_89

The largest area, Polynesia, stretching from Hawaii in the north to New Zealand in the south, also encompasses Tuvalu, Tokelau, Samoa, Tonga and the Kermadec Islands to the west, the Cook Islands, Society Islands and Austral Islands in the center, and the Marquesas Islands, Tuamotu, Mangareva Islands, and Easter Island to the east. Pacific Ocean_sentence_90

Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Pacific Ocean_sentence_91

Continental islands lie outside the andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Pacific Ocean_sentence_92

Some of these islands are structurally associated with nearby continents. Pacific Ocean_sentence_93

High islands are of volcanic origin, and many contain active volcanoes. Pacific Ocean_sentence_94

Among these are Bougainville, Hawaii, and the Solomon Islands. Pacific Ocean_sentence_95

The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under the ocean's surface. Pacific Ocean_sentence_96

One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. Pacific Ocean_sentence_97

A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Pacific Ocean_sentence_98

Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia. Pacific Ocean_sentence_99

Pacific Ocean_unordered_list_0

  • Pacific Ocean_item_0_0
  • Pacific Ocean_item_0_1
  • Pacific Ocean_item_0_2
  • Pacific Ocean_item_0_3

Water characteristics Pacific Ocean_section_11

The volume of the Pacific Ocean, representing about 50.1 percent of the world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles). Pacific Ocean_sentence_100

Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of sea water, in the poleward areas to about 30 °C (86 °F) near the equator. Pacific Ocean_sentence_101

Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. Pacific Ocean_sentence_102

The water near the equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. Pacific Ocean_sentence_103

The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas. Pacific Ocean_sentence_104

The motion of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific gyre) and counter-clockwise in the Southern Hemisphere. Pacific Ocean_sentence_105

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. Pacific Ocean_sentence_106

Turning eastward at about 45°N, the Kuroshio forks and some water moves northward as the Aleutian Current, while the rest turns southward to rejoin the North Equatorial Current. Pacific Ocean_sentence_107

The Aleutian Current branches as it approaches North America and forms the base of a counter-clockwise circulation in the Bering Sea. Pacific Ocean_sentence_108

Its southern arm becomes the chilled slow, south-flowing California Current. Pacific Ocean_sentence_109

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 South Pacific, which includes the Earth-circling Antarctic Circumpolar Current. Pacific Ocean_sentence_110

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. Pacific Ocean_sentence_111

Climate Pacific Ocean_section_12

The climate patterns of the Northern and Southern Hemispheres generally mirror each other. Pacific Ocean_sentence_112

The trade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on the east coast of Russia contrasting with the milder weather off British Columbia during the winter months due to the preferred flow of ocean currents. Pacific Ocean_sentence_113

In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions. Pacific Ocean_sentence_114

To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately 3,000 km (1,900 mi) to the southeast of Hawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then an El Niño or La Niña is considered in progress. Pacific Ocean_sentence_115

In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Pacific Ocean_sentence_116

Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. Pacific Ocean_sentence_117

On a worldwide scale, May is the least active month, while September is the most active month. Pacific Ocean_sentence_118

November is the only month in which all the tropical cyclone basins are active. Pacific Ocean_sentence_119

The Pacific hosts the two most active tropical cyclone basins, which are the northwestern Pacific and the eastern Pacific. Pacific Ocean_sentence_120

Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the southwestern United States between June and October, while typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Pacific Ocean_sentence_121

Tropical cyclones also form in the South Pacific basin, where they occasionally impact island nations. Pacific Ocean_sentence_122

In the arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. Pacific Ocean_sentence_123

A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. Pacific Ocean_sentence_124

The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between the tropics and Antarctica, which records the coldest temperature readings on the planet. Pacific Ocean_sentence_125

In the Southern hemisphere, because of the stormy and cloudy conditions associated with extratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude. Pacific Ocean_sentence_126

Geology Pacific Ocean_section_13

Main articles: Geology of the Pacific Ocean and Pacific Plate Pacific Ocean_sentence_127

The ocean was first mapped by Abraham Ortelius; he called it Maris Pacifici following Ferdinand Magellan's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. Pacific Ocean_sentence_128

To Magellan, it seemed much more calm (pacific) than the Atlantic. Pacific Ocean_sentence_129

The andesite line is the most significant regional distinction in the Pacific. Pacific Ocean_sentence_130

A petrologic boundary, it separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins. Pacific Ocean_sentence_131

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's North Island. Pacific Ocean_sentence_132

The dissimilarity continues northeastward along the western edge of the Andes Cordillera along South America to Mexico, returning then to the islands off California. Pacific Ocean_sentence_133

Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside the andesite line. Pacific Ocean_sentence_134

Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Pacific Ocean_sentence_135

Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Pacific Ocean_sentence_136

Outside the andesite line, volcanism is of the explosive type, and the Pacific Ring of Fire is the world's foremost belt of explosive volcanism. Pacific Ocean_sentence_137

The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones. Pacific Ocean_sentence_138

The Pacific Ocean is the only ocean which is mostly bounded by subduction zones. Pacific Ocean_sentence_139

Only the Antarctic and Australian coasts have no nearby subduction zones. Pacific Ocean_sentence_140

Geological history Pacific Ocean_section_14

The Pacific Ocean was born 750 million years ago at the breakup of Rodinia, although it is generally called the Panthalassa until the breakup of Pangea, about 200 million years ago. Pacific Ocean_sentence_141

The oldest Pacific Ocean floor is only around 180 Ma old, with older crust subducted by now. Pacific Ocean_sentence_142

Seamount chains Pacific Ocean_section_15

The Pacific Ocean contains several long seamount chains, formed by hotspot volcanism. Pacific Ocean_sentence_143

These include the Hawaiian–Emperor seamount chain and the Louisville Ridge. Pacific Ocean_sentence_144

Economy Pacific Ocean_section_16

The exploitation of the Pacific's mineral wealth is hampered by the ocean's great depths. Pacific Ocean_sentence_145

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. Pacific Ocean_sentence_146

Fishing Pacific Ocean_section_17

Fish are an important economic asset in the Pacific. Pacific Ocean_sentence_147

The shallower shoreline waters of the continents and the more temperate islands yield herring, salmon, sardines, snapper, swordfish, and tuna, as well as shellfish. Pacific Ocean_sentence_148

Overfishing has become a serious problem in some areas. Pacific Ocean_sentence_149

For example, catches in the rich fishing grounds of the Okhotsk Sea off the Russian coast have been reduced by at least half since the 1990s as a result of overfishing. Pacific Ocean_sentence_150

Environmental issues Pacific Ocean_section_18

Main article: Marine pollution Pacific Ocean_sentence_151

See also: Great Pacific garbage patch and Environmental impact of shipping Pacific Ocean_sentence_152

The quantity of small plastic fragments floating in the north-east Pacific Ocean increased a hundredfold between 1972 and 2012. Pacific Ocean_sentence_153

The ever-growing Great Pacific garbage patch between California and Japan is three times the size of France. Pacific Ocean_sentence_154

An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8 trillion pieces. Pacific Ocean_sentence_155

Marine pollution is a generic term for the harmful entry into the ocean of chemicals or particles. Pacific Ocean_sentence_156

The main culprits are those using the rivers for disposing of their waste. Pacific Ocean_sentence_157

The rivers then empty into the ocean, often also bringing chemicals used as fertilizers in agriculture. Pacific Ocean_sentence_158

The excess of oxygen-depleting chemicals in the water leads to hypoxia and the creation of a dead zone. Pacific Ocean_sentence_159

Marine debris, also known as marine litter, is human-created waste that has ended up floating in a lake, sea, ocean, or waterway. Pacific Ocean_sentence_160

Oceanic debris tends to accumulate at the center of gyres and coastlines, frequently washing aground where it is known as beach litter. Pacific Ocean_sentence_161

From 1946 to 1958, Marshall Islands served as the Pacific Proving Grounds for the United States and was the site of 67 nuclear tests on various atolls. Pacific Ocean_sentence_162

Several nuclear weapons were lost in the Pacific Ocean, including one-megaton bomb lost during the 1965 Philippine Sea A-4 incident. Pacific Ocean_sentence_163

In addition, the Pacific Ocean has served as the crash site of satellites, including Mars 96, Fobos-Grunt, and Upper Atmosphere Research Satellite. Pacific Ocean_sentence_164

Major ports and harbors Pacific Ocean_section_19

Main article: List of ports and harbors of the Pacific Ocean Pacific Ocean_sentence_165

See also Pacific Ocean_section_20

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: Ocean.