East Pacific Rise

The East Pacific Rise is the fast-spreading mid-ocean ridge between the Pacific and the Nazca and Cocos plates. Its full spreading rate reaches about 15 to 20 cm/yr near the equator, among the fastest on Earth, and historic rates exceeded 20 cm/yr. Fast spreading gives it a smooth, broad cross-section with no deep axial rift valley, the opposite of the rugged slow Mid-Atlantic Ridge. The crest hosts dense black-smoker vent fields, including the 21 degrees North site where high-temperature hydrothermal venting was first observed in 1979. Its rapid crust production makes its magnetic stripes wide and easy to date.