Mid-oceanic ridge at a divergent tectonic plate boundary on the floor of the Pacific Ocean
Approximate surface projection on Pacific Ocean of East Pacific Rise (purple). In some usage this continues as the
Pacific-Antarctic Ridge (violet). Features associated with fracture zones (orange) are also shown (lighter orange). Click to expand map to obtain interactive fracture zone details.[1]
The
oceanic crust is moving away from the East Pacific Rise to either side. Near
Easter Island the rate is over 150 mm (6 in) per year which is the fastest in the world.[2] However, on the northern end, it is much slower at only roughly 60 mm (2+1⁄2 in) per year.[3][4] On the eastern side of the rise, the eastward-moving
Cocos and
Nazca plates meet the westward moving
South American Plate and the
North American Plate and are being
subducted under them. The belt of
volcanos along the
Andes and the arc of volcanoes through
Central America and
Mexico are the direct results of this collision. Due east of the
Baja California Peninsula, the Rise is sometimes referred to as the
Gulf of California Rift Zone. In this area, newly formed oceanic crust is intermingled with rifted continental crust originating from the North American Plate.
Near
Easter Island, the East Pacific Rise meets the
Chile Rise at the Easter Island and Juan Fernandez microplates, trending off to the east where it subducts under the
South American Plate at the
Peru–Chile Trench along the coast of southern
Chile. This portion of the Rise has been referred to as the Cape Adare-Easter Island Ridge, Albatross Cordillera, Easter Island Cordillera, Easter Island Rise, and Easter Island Swell.[5]
Parts of the East Pacific Rise have oblique spreading, such as the Nazca–Pacific plate boundary between 29°S and 32°S.[6] This is
seafloor spreading that is not orthogonal to the nearest ridge segment.[6]