Pacific–Farallon Ridge

[2] On average, this ridge had an equatorial spreading rate of 13.5 cm per year until its eventual collision with the North American Plate.

The most notable remnant of the Pacific-Farallon Ridge is the 4000 km Pacific-Nazca segment of the East Pacific Rise.

[5] The spreading rate decreased once the ridge made contact with the North American Plate 16 million years ago.

[7] Once the Pacific-Farallon Ridge began subducting beneath the North American Plate, the remains of the Farallon Plate broke apart to form the Monterey, Arguello, Magdalena, and Guadelupe Microplates, and the southern portion of the ridge rotated in a clockwise manner.

[9] As the Pacific-Farallon Ridge began its subduction underneath the North American plate 30 million years ago, its southern segment, the East Pacific Rise continued spreading.

Relative velocity vectors of Pacific, Farallon, and Kula plates 55 million years ago (Black represents present-day land area)
Formation of the Juan de Fuca (including Explorer and Gorda) and Cocos plates (including Rivera) and of the San Andreas Fault from the Farallon plate