The Pacific Ocean
is the largest ocean in the world!

What’s in a Name?

The Pacific Ocean was named by legendary navigator Ferdinand Magellan. A native of Portugal, Magellan renounced his loyalty to that nation after King Emanuel rejected Magellan’s petition for a post within the royal navy. Magellan then left for Spain, which agreed to support Magellan’s claim of a western route to the Spice Islands through a seaway near the southern tip of South America.

On September 20, 1519, Magellan and a crew of 270 men set sail from Spain on their around-the-world voyage in five small vessels including his flagship Trinidad, Concepcion, San Antonio, Victoria, and Santiago. It took the fleet, or at least the three remaining ships in the fleet, 38 days to navigate the strait around South America that was to bear Magellan’s name. During the last week of November, the fleet emerged into what Magellan described as a “beautiful, peaceful ocean.” Thus, it was named the Pacific Ocean (“pacific” meaning “peaceful.”)

Upon entering the Pacific Ocean, Magellan mistakenly thought the Spice Islands were only a short voyage away. Nearly four months later, in March 1521, he and his crew finally reached what is known today as the Philippines. A few weeks later, he was fatally wounded after becoming involved in a dispute between warring Philippine tribes. Only one ship, Victoria, and 18 of Magellan’s original crew members returned to Spain, thereby completing the first circumnavigation of the globe. Although Magellan’s route proved impractical for the spice trade, his voyage has been called the greatest single human achievement on the seas.


Total Area :

The Pacific Ocean is the largest of the world’s five oceans, followed by the Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean. It covers an area of about 155 million square kilometers (about 60 million square miles). It is larger than the total land area of the world and about 15 times the size of the United States.



Its average depth is 4,637 meters (2.8 miles). It is home to the deepest known point in the ocean — the Mariana Trench off Guam — which plunges to a depth of about 10,924 meters (nearly 7 miles). Because of the depth of the Pacific Ocean, tsunamis (huge waves created by earthquakes) can reach speeds of 750 kilometers an hour, the same velocity as a jet airplane.


Nations & Islands:

Seventeen independent nations are located in the Pacific: Australia, Fiji, Japan, Kiribati, Marshall Islands, Micronesia, Nauru, New Zealand, Palau, Papua New Guinea, the Philippines, Samoa, Solomon Islands, Taiwan, Tonga, Tuvalu, and Vanuatu. The U.S. state of Hawaii is also located here and several island territories and possessions of Australia, Chile, France, Japan, New Zealand, United Kingdom, and the United States.

The largest land mass in this ocean is the continent of Australia, which is about equal in size to the 48 contiguous states of the United States. There are some 25,000 islands in the Pacific Ocean — which is more than the rest of the world's oceans combined. Almost all the smaller islands lie between 30°N and 30°S latitude, extending from Southeast Asia to Easter Island. The rest of the Pacific Basin is almost devoid of land.



The ocean and the atmosphere are closely linked — a fact that is clearly demonstrated by the global weather phenomena we know as "El Niño" and "La Niña," which arise in the Pacific Ocean. Ages ago, Peruvian fishermen named the seasonal warming of the waters off their coast, which occurs in December, "El Nino," which is Spanish for "the Christ child." During a normal year, the waters off South America are typically cold and highly productive for fishing. Then in December (which is summer in the Southern Hemisphere), the water normally warms and fishing becomes less productive. Cold water usually returns again in June, when the fishing season begins again there. In some years, however, the water stays warm throughout the year and can cause dramatic weather around the world. The term "El Niño" is now used to refer to this climatic process.

Steady, westward-blowing trade winds cause warm water to pile up in the western Pacific. During El Niño, the trade winds weaken and cannot "contain" this huge pool of warm water. Consequently, warm water extends far eastward. In the United States, the effects of an El Niño winter include warmer than normal temperatures from the Great Lakes to Alaska, wetter than normal conditions across the southern tier of states, some dryness in the Midwest, and cooler than normal temperatures in the Southeast. It can also include a decrease in hurricanes that reach land.

In some ways, La Niña is the opposite of El Niño and is characterized by cooler than normal ocean water surface temperatures in the central tropical Pacific. In the United States, a La Niña winter includes temperatures that are cooler than normal over the Northwest, warmer than normal over the Southeast, drier than normal from Florida to Arizona, and wetter than normal over the Pacific Northwest and parts of the Midwest. La Niña may also bring an increase in hurricanes that reach land in the United States.

According to the NOAA National Weather Service's Climate Prediction Center, it's likely that El Niño conditions will persist through early 2005. Among the expected impacts around the globe are drier-than-average conditions in Indonesia (through early 2005), northern and northeastern Australia (Nov. 2004 – Feb. 2005), and southeastern Africa (Nov. 2004–March 2005). If the warming in the tropic Pacific strengthens and spreads eastward to the South American coast, then wetter-than-average conditions would be expected in coastal sections of Ecuador and northern Peru during the first few months of 2005, and drier-than-average conditions would be expected to develop in the eastern Amazon late this year and spread to northeast Brazil during Feb.–April 2005.


Bottom Terrain:

The ocean floor in the eastern Pacific is dominated by the East Pacific Rise, which is a part of the worldwide Mid-Ocean Ridge system. About 3,000 km (1,800 mi) across, the rise stands about 3 km (2 mi) above the adjacent ocean floor. The western part of the Pacific Ocean floor consists of mountain arcs that rise above the sea as island groups, such as the Solomon Islands and New Zealand, and deep trenches, such as the Mariana Trench, the Philippine Trench, and the Tonga Trench. Most of the deep trenches lie adjacent to the outer margins of the wide western Pacific continental shelf.


Natural Resources:

One of the Pacific Ocean’s greatest assets is fish, including herring, salmon, sardines, snapper, swordfish, tuna, and shellfish. In 1996, over half (60%) of the world’s total fish catch came from the Pacific Ocean. Pearls are harvested along Australia, Japan, Papua New Guinea, Nicaragua, Panama, and the Philippines. Exploitation of offshore oil and gas reserves is playing an ever-increasing role in the energy supplies of Australia, New Zealand, China, the United States, and Peru.



The Pacific Ocean’s endangered marine species include the dugong, sea lion, sea otter, seals, turtles, and whales. Current major environmental issues include oil pollution in the Philippine Sea and South China Sea. In terms of natural hazards, the Pacific Ocean is surrounded by a zone of violent volcanic and earthquake activity (“The Ring of Fire”). Hurricanes may form south of Mexico and strike Central America and Mexico from June to October. The greatest typhoon frequency exists within the triangle from southern Japan to the central Philippines to eastern Micronesia.



Bangkok (Thailand), Hong Kong, Kao-hsiung (Taiwan), Los Angeles (U.S.), Manila (Philippines), Pusan (South Korea), San Francisco (U.S.), Seattle (U.S.), Shanghai (China), Singapore, Sydney (Australia), Vladivostok (Russia), Wellington (New Zealand), Yokohama (Japan).



CIA Fact Book: Pacific Ocean, Central Intelligence Agency
Ferdinand Magellan, The Mariners’ Museum, Newport News, Virginia
The Magellan Venus Explorer’s Guide, NASA Jet Propulsion Lab
The Pacific Ocean, Office of the Oceanographer of the Navy


Copyright University of Delaware.