The infamous San Andreas fault is the border between the North American and the Pacific tectonic plates. This fault lies in California and is responsible for some of the major earthquakes that occur there. Los Angeles is on the Pacific Plate but San Francisco is on the North American Plate. The Pacific Plate is sliding northward with respect to the North American Plate and, as a result, Los Angeles gets about half an inch closer to San Francisco every year. In a few million years, the two cities will be neighbors.