When two plates slide past each other they create a conservative plate margin. The relative movement is horizontal, and classified as either sinistral (moving to the left) or dextral (moving to the right). Along these margins crust (lithosphere) is not being destroyed by subduction, neither is it being created. There is no melting of rock, and, therefore, no volcanic activity or formation of new crust. Despite the absence of volcanic activity, these margins are tectonically extremely active and are associated with powerful, considerable magnitude, earthquakes, being the sites of extensive shallow focus earthquakes. Transfer faults are mainly found on the ocean floor, where they offset mid ocean ridges and enable the ocean floor to spread at different rates. At conservative plate boundaries, there are very few features to be seen, save for the large crack that forms in the ground where two separate plates are moving against each other. Sometimes there is known to be some cliff forming along the fault line.
The San Andreas Fault:
The San Andreas Fault is a continental transform fault that extends roughly 810 miles (1,300 km) through California in the United States. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip(horizontal). The fault divides into three segments, each with different characteristics, and a different degree of earthquake risk. Although the most significant (Southern) segment only dates back about 5 million years, the oldest sections were formed by the subduction of a spreading ridge 30 million years ago.
The northern segment of the fault runs from Hollister, through the Santa Cruz Mountains, epicenter of the 1989 Loma Prieta earthquake, then on up the San Francisco Peninsula, where it was first identified by Professor Lawson in 1895, then offshore at Daly City near Mussel Rock. This is the approximate