The Pacific Ocean

The Pacific Ocean is the largest and deepest of the world ocean basins. Covering approximately 63 million square miles and containing more than half of the free water on Earth, the Pacific is by far the largest of the world’s ocean basins. The world ocean is divided by convention into three basins: the Arctic, the Atlantic, and the Pacific. Other subdivisions of the ocean are more speculative or less scientifically accepted.

The Pacific Ocean was created about 30 million years ago when the northern part of Gondwanaland broke away from South America and drifted northward to its present location. This occurred after a series of volcanic events began forming islands in this location making it much easier to do so than in other locations. 10 million years later the Pacific began to sub-divide as the Nazca Plate and Carnegie Ridge subducted under the South American Plate. The southern section of the Pacific Ocean was then free to move northward, splitting into what are now Tasman Sea, Coral Sea, and East Pacific Rise.

The Pacific Ocean is bounded by Asia on the north, on the east by Australia and Antarctica, on the south by South America, and on the west by North America. The Pacific Ocean meets the Atlantic Ocean in an area called the “Pacific Intertropical Convergence Zone” (ITCZ) and the two largest oceanic trenches in the world: the Mariana and Philippine Trenches (see map). The Pacific Ocean is filled with islands; most to the west of the International Date Line, but some 7,615 islands can be found to its east.

The Pacific is also home to five of Earth’s seven continents – Australia, Antarctica, Asia, North America, and South America. In that order from the smallest to the largest – although the continental proportions of Asia and Australia are by far greater than those of North and South America.

The Pacific Ocean is a very active oceanic basin, with a rich history of island formation, volcanic activity, earthquakes and mountain building. The Pacific Ocean has a deep oceanic trench, named after one of its seamounts, running almost its entire length from Mexico to Indonesia. Over this span, it drops at most 7 miles. It is estimated to have produced about 25% of the Earth’s current earthquake activity, with an average rate of 45.5 earthquakes per year. The largest flood basalt event in earth’s history, the Mariana flood basalt event, is also estimated to have occurred in the Pacific Ocean.

The International Hydrographic Organization (IHO) defines the limits of the “Pacific Ocean” as follows:

“On the North.” The coast of Antarctica (65°S).

“On the East.” A line drawn between a point in South latitude 60°S and a point in North latitude 80°N.

“On the South.” The Antarctic coast (73°S)

“On the West.” The coast of Australia (153°E)”.

The “Pacific Ocean” is defined to include all other bodies of water contained within these boundaries except: 1.) any sea which, by agreement between 21 countries, is divided into two or more parts; 2. All seas not included in the limits of the “Pacific Ocean” as defined above; and 3.) The Arctic Ocean.

The IHO “Pacific Ocean” is further subdivided into 13 sub-regions:

Regions Sub-Regions North East (NE) North (N) Western (W) Central (C) Eastern (E) South West (SW) South East (SE) Sub-Region 1, 2, 3, 4, 5, 6 and 7. 8 and 9. 10 and 11. 12. 13.

The North-East Pacific is divided into two separate sections, otherwise known as the North Pacific and the Bering Sea. The North Pacific is approximately 20 million square miles in size and includes the Bering Sea. The eastern edge is defined by the continental shelf of Asia, Africa and Australia which runs along most of North America’s West Coast, South America’s West Coast and southern Europe. The western edge of this region is defined by the deep ocean floor. The North Pacific is mostly covered by the featureless North Pacific featureless abyssal plain, save for relatively small island chains, such as the Aleutian Islands.

The North-East Pacific is divided into two separate sections, otherwise known as the North Pacific and the Bering Sea. The North Pacific is approximately 20 million square miles in size and includes the Bering Sea. The eastern edge is defined by the continental shelf of Asia, Africa and Australia which runs along most of North America’s West Coast, South America’s West Coast and southern Europe. The western edge of this region is defined by the deep ocean floor. The North Pacific is mostly covered by the featureless North Pacific featureless abyssal plain, save for relatively small island chains, such as the Aleutian Islands.

The North Pacific is a subsection of the North-East Pacific. It includes the Bering Sea and the deep ocean floor. The North Pacific has a very rich history of island production, volcanic activity and earthquake activity among others.

The Western Pacific is a subsection of the North-East Pacific. It includes most of Asia, Oceania and nearly all of the South American coast including coastal regions of Africa, Antarctica and Australia.
The North Pacific is a subsection of the North-East Pacific. It includes the Bering Sea and the deep ocean floor. The North Pacific has a very rich history of island production, volcanic activity and earthquake activity among others.

A relatively small subsection of the western Pacific compared to its other subregions, Central Pacific is bordered by South America, Asia and Oceania including its many islands. This region includes the Hawaiian Islands as well as smaller island groups such as Micronesia, Kiribati, Fiji and Tonga.

The Eastern Pacific is bounded by Cape Horn to the west and South America to the east. This region includes the boundary of the North Pacific. Central Pacific is bordered by Asia and Oceania including its nearly 6,000 islands. The Hawaiian Islands are also located in this area.

The South-West Pacific is similar in many ways to its eastern counterpart, except that it has far more islands, ranging from 3,000 volcanic islands along its coastlines to over 750 thousand small islands scattered across the vast ocean floor.

The South-East Pacific is the smallest of the subregions. It includes the Juan Fernández Islands off the coast of Chile, Easter Island, Chiloé Archipelago, Rapa Nui (Easter Island) and Salas y Gómez Islands.

Permanent human habitation of the Pacific islands began with colonization by Austronesian people from Taiwan between 3500 BC to 1500 BC. The Polynesians later settled New Zealand, Hawaii and Easter Island between 1200 BC to 500 AD. Permanent human habitation in Polynesia began around AD 300 when the Lapita people migrated from the Bismarck Archipelago in Micronesia to the islands of Samoa and Tonga (then known as Te I’inga).

During the later part of Maori Colonization, canoe voyages were made between Eastern Polynesia and New Zealand. It is also thought that visits by Motu Māori (indigenous people of New Zealand) to Eastern Polynesia may have happened in ancient times.

In the last decades of the 16th century, Spanish explorers visited the Pacific Islands. In 1567–68, Álvaro de Mendaña was the first European to reach Guam and the Mariana Islands. From then until 1595, a “Guam” or “Ladrones” expedition visited most of the principal islands in the group on several occasions. In 1595, the Spanish navigator Alonso de Arellano landed in the Marshall Islands and visited Tikopia in 1606.

In 1762, Louis Antoine de Bougainville sailed for French Polynesia (now called the Society Islands). In 1768, James Cooks’s three HMS ships visited Tahiti and other islands. In 1769, he also became the first European to visit New Zealand. In 1773, the crew of the American ships discovered Easter Island. In 1789, Admiral Roggeveen discovered the Samoan Islands and Malukula. In 1795–96, William Bligh led a mutiny on his ship, HMS “Bounty” for a long-distance voyage to Tahiti from England which ended in mutiny and cannibalism.

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