The Pacific and North American tectonic plates are slipping past each other along the San Andreas fault, about two inches each year. Los Angeles, which sits of the edge of the Pacific Plate, is slowly moving northward, at about the same speed as the growth of fingernails. At the same time, San Francisco, which sits on the edge of the North American Plate, is moving southward. Los Angeles City Hall is now more than 15 feet closer to San Francisco than when it was built in 1926. Scientists project that it should be located in the suburbs of San Francisco in approximately 15 million years.