A photo of San Andreas Fault

This is a zoomed-in view looking south along the trace of the San Andreas Fault from the top of the fault scarp at Wallace Creek. Note the many stream channels on the uphill side of the fault (toward the Temblor Range). In contrast, the streams on the downhill side are less prominent or are consolidated. The trace of the fault runs down the east side of the Elkhorn Hills, the low hills in the upper-center part of the image. The high peaks of the Sierra Madre Range wilderness rise beyond the Caliente Range in the distance.

Studies of beheaded channels (streams whose uphill source have been separated by fault motion) show that major earthquakes have occurred in the Wallace Creek area in prehistoric times. Studies suggest either two or three major earthquakes occurred in the region between around 250 A.D. and the great quake in 1857. Research by Sieh and Wallace (1987) suggests earthquake-associated offset of about 40.6 feet occurred between 1540 and 1630 A.D., and another offset of about 36 feet may have occurred between 1120 and 1300 A.D. Based on these estimates; these authors predicted that the next major earthquake in this area might occur around 2100 A.D. or later.