What Surface Features Characterize It?
Over much of its length, a linear trough reveals the
presence of the San Andreas fault; from the air, the linear
arrangement of lakes, bays, and valleys in this trough is
striking. Viewed from the ground, however, the features are more
subtle. For example, many people driving near Crystal Springs
Reservoir, near San Francisco, or along Tomales Bay, or through
Cajon or Tejon Passes may not realize that they are within the
San Andreas fault zone. On the ground, the fault can be
recognized by carefully inspecting the landscape. The fault zone
is marked by distinctive landforms that include long straight
escarpments, narrow ridges, and small undrained ponds formed by
the settling of small blocks within the zone. Many stream
channels characteristically jog sharply to the right where they
cross the fault.
A stream channel offset by the San Andreas fault, Carrizo Plain, central California
(photo by Robert E. Wallace)
Full size image - 119k.
U.S. Department of the Interior |
U.S. Geological Survey