Elkhorn Scarp Along San Andreas Fault
November 17, 2006
When it comes to revealing a fault, few places in the world can compare to the Carrizo Plain National Monument. Located in central California, the area is home to part of the San Andreas Fault and contains some astonishing landforms. The fault is the sliding boundary separating the North American Plate and the Pacific Plate. Here a particularly dramatic part of the fault, called the Elkhorn Scarp, can be seen. The fault lies along the obvious top-to-bottom trough and crossing it are many small erosional valleys. Together they form the “Dragon’s Back,” a long linear ridge with many regularly-spaced serrations. The Elkhorn Scarp is part of a pressure ridge, a region that has been uplifted as the two plates are forced together. While most of the motion is transverse and the plates grind horizontally past each other, a small compressional component has raised the Elkhorn Scarp. The picture was taken from an altitude of about 5,500 feet (1,677 m) and is about a mile (1.6 km) from left edge to right edge at mid-picture.