Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.
At 169.2 million square kilometres (65.3 million square miles) in area, this largest division of the World Ocean and, in turn, the hydrosphere covers about 46% of the Earth's water surface and about 30% of its total surface. The equator subdivides it into the North Pacific Ocean and South Pacific Ocean, with two exceptions: the Galapagos and Gilbert Islands, while straddling the equator, are deemed wholly within the South Pacific. The Mariana Trench in the western North Pacific is the deepest point in the Pacific and in the world, reaching a depth of 10,911 metres (35,797 ft).
The Pacific Ocean was sighted by Europeans early in the 16th century, first by the Spanish explorer Vasco Nunez de Balboa who crossed the Isthmus of Panama in 1513 and named it Mar del Sur (South Sea). Its current name is however derived from the Luso-Latin macaronic Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan.
Overview
The 'Pacific Ocean' encompasses approximately 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 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 5N latitude, where it stretches approximately 19,800 kilometres (12,300 mi) from Indonesia to the coast of Colombia and Peru - halfway across the world, and more than five times the diameter of the Moon. The lowest known point on earth-the Mariana Trench-lies 10,911 metres (35,797 ft) below sea level. Its average depth is 4028~4188metres (14,000 ft).
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. Including partially submerged islands, the figure is substantially higher.
The Pacific Ocean is currently shrinking from plate tectonics, while the Atlantic Ocean is increasing in size, by roughly an inch per year (2-3 cm/yr) on 3 sides, roughly averaging 0.2 square miles (0.5 km2) a year.
Storm in Pacifica, California
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 Drake Passage and the Straits of Magellan link 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 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.
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 storms 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.
Geology
The andesite line is the most significant regional distinction in the Pacific. 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. 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.
The dissimilarity continues northeastward along the western edge of the Andes 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 Asia, Australia and Zealandia-lie outside the Andesite Line.
The Pacific Ocean takes up roughly one third of the Earth's surface, having an area of 179.7 million square kilometres. It 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, Including partially submerged islands. The ocean was mapped by a man named Abraham Ortelius, he called it Maris Pacifici because of Ferdinand Magellan, who sailed the Pacific during his circumnavigation from 1519 to 1522 and said that it was much more calm than the Atlantic.
The Pacific Ocean has several long seamount chains (which are chains of mountains submerging from the ocean seafloor) formed by hotspot volcanism. "The Ring of Fire" is the world's largest belt of explosive volcanism. It is named after the several hundred active volcanoes that sit above the various subduction zones(which is a geological process in which one edge of a crustal plate is forced sideways and downward into the mantle below another plate).
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. 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 of explosive volcanism. The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones.
The Pacific Ocean is the only ocean which is almost totally bounded by subduction zones. Only the Antarctic and Australian coasts have no nearby subduction zones.
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