How is the San Andreas Fault explained by the theory of plate tectonics?

The Transform Boundary (or Strike-Slip Fault) is caused by two plates pushing against each other. Few actually occur on land, most happen on the seafloor. Transform boundaries often create split stream beds, with the water flowing off in different directions, or valleys where the rocks have been ground up by the sliding plates. Many earthquakes are caused by Transform Boundaries' movement, although most are quite shallow.

The San Andreas Fault, running through two-thirds of California, is one of the few transform boundaries found on land. It has a length of 1300km and in some areas is tens of kilometres wide, moving approximately 5cm per year. For the last 10 million years, the North American and Pacific plates have been sliding against each other, forming the San Andreas Fault. It separates two diverging boundaries; the East Pacific Rise and the Juan de Fuca.