The Oceano Pacífico is the largest marine mass of the globe, located among America, to East, Asia and Australia, the West, and Antártida, to the South. With 180 million km², Pacific almost collects a third of the surface of the planet and it almost corresponds the half of the surface and of the volume of the ocean [he/she has 707,5 km of fossas, and 87,8% of its area it presents superior depths to 3.000 m; it is the ocean with larger medium depth (-4.282 m) and where they are located the largest submarine fossas (fossa of Marianas, with -10,912 m)]. Its form grossly to circulate is defined by margins continental activas (that correspond to the I circulate of fire of Pacific) under which he/she sinks an oceanic crust in fast expansion. Discovered by the Europeans in 1513 (Balboa) and transposed for the first time in 1520 (Fernão of Magalhães), Pacific has been attending a growth of its importance as connection road among some of the areas of larger economic dynamism of the present time (I Carry to an extreme East and western coast of North America). Flanked by recent mountainous chains, with intense volcanic activity, Pacific is traveled by a vast system of number. The number Southeast-peaceful it constitutes a prolongation, through number Pacific-Antarctica, of the number of Indian Ocean (number Antarctic-Autraliana). In its northern portion it reaches the latitudes of the Mexican coast, disappearing when penetrating in the golf of California. It is a number one in fast expansion (between 8,8 and 16,1cm a year), without axial fossa. The zones of fractures that segment it are numerous, with pronounced displacement. That number one emerges in the latitude of the island of Passover, joining to the number of Chile, that links to the southern coast of America, and in the latitude of the islands Galápagos, joining to the number of Coconuts or of Galápagos. Those number ones divide Pacific in three groups. The located oceanic funds the Southeast-peaceful East of the number belongs the plate litosférica of Antártida (that corresponds to the basin Pacific-Antarctica and to the plain abissal of Bellingshausen), to the plate of Nazca (Peruvian and Chilean basins, separated by the number of Nazca) and to the plate of Coconuts (limited by the number of Coconuts). The whole immense group of located oceanic funds the Southeast-peaceful West of the number is sustained by the plate Peaceful litosférica, that to West North America presents great zones of fractures, with monumental reliefs, aligned by thousands of kilometers along old transformation flaws. Plus to West, the center of the ocean Pacific is interrupted by submarine chains and great volcanic buildings, for now emerging in form of islands (Hawaii, Marquises, Marshall, Carolinas), frequently crowned by coralline formations (atolls). The oceanic basins that surround them (Medium-peaceful, Melanésia, Northeast, Northwest) they present a vicarial sedimentary covering on the basaltic crust. The presence of the outlying oceanic fossas, along the insular arches (Aleutas, Kurilas, Japan, Marianas, Philippines, Salomão, Tonga, Kermadec) and of the western coast of America (Chile, Peru, Central America) it is explained for they correspond to zones of subducção of the oceanic crust, in that is it dives under the plates American litosféricas, the East, and Eurasiática and Go-Australian, to West. They are areas of intense seismic and volcanic activity, subject to the occurrence of maremotosconformação of the basins of Pacific it explains the relative simplicity of the marine currents that there happen. The currents north-equatorial and south-equatorial they move of east for west, determining the existence of hot currents along the oriental facades of the continents, compensated by cold currents that go down for the equator along the western facades (places privileged for the fishing in great scale). In the medium latitudes, the hot currents at issue they meet with the coming cold waters of the polar areas. Such phenomenon is particularly clear in Northern Hemisphere, where Kuroshio, hot, meets with Oyashio, cold, to the plaza of Japan. In general, the salinity of the waters is not very high, because the maximum values never surpassed 365 for thousand. The temperatures of the surface waters are disposed in zones, increasing of the poles for the tropics. The heat of the waters of the zone intertropical allows the proliferation of the chorales, that form islands (atolls) or barriers (reefs) in the continental borders. Already in the waters more piscosas they locate in the temperate latitudes, where revolving of the currents guarantees excellent hoxigenáçao.