Transform plate boundaries form in the continents to link convergent and divergent plate boundaries. The San Andreas fault in California formed as a result of subduction of a section of the midocean ridge. The San Andreas fault can be thought of as essentially a very long offset transform fault connecting spreading centers in the Gulf of California and off the Pacific Northwest.

Although we think of the ideal case of only shear stress along a transform boundary, if the transform fault is not straight compressional and tensional stresses are also generated. Restraining bends result in compression. Releasing bends result in extension and deep basins (pull-apart basins) form.

Faulted Features - Strike-Slip Faults

Offset Features: Strike-slip fault are vertical faults that form as a result of shearing stress such as near transform plate boundaries. Offset streams, fences, roads, etc. are clear signs of active fault motion. For example, some streets in the San Francisco Bay area are being offset at a rate of more than an inch per year. The maximum displacement on the San Andreas Fault during the great 1906 earthquake was about 25 feet, which occurred in essentially one sudden motion. Ridges and drainage divides may be offset by an active strike-slip fault. The split and mismatched ridges are called shutter ridges.

Compressional and Extensional Features: Faults are seldom perfectly planar or perfectly linear features. The line of the San Andreas and most other long strike-slip faults found on the continents contains bends. Releasing bends allow separation to occur on opposite sides of the fault. Subsiding basins called pull-apart basins or rhomb grabens form at these bends. The Dead Sea and San Francisco Bay are two modern pull-apart basins. The Ridge Basin of southern California is an extinct pull-apart basin filled with around 13 kilometers of sediments. At restraining bends the opposite sides of the fault converge forming push-up ranges (rhomb horsts).

Rotated Features: Many continental transforms (unlike oceanic transforms) are typified by a wide zone of deformation. It is better to think of the San Andreas fault zone. There are scores of faults, mostly strike-slip slicing portions of California. Crustal blocks lying between faults may behave as ball bearings rotating between two plates. The trend of the Transverse Ranges of southern California runs approximately east-west, inconsistent with all of the northwest-southeast trending coastal ranges. The Transverse Ranges are believed to have rotated more than 90 degrees clockwise as a result of right-lateral shearing in the San Andreas Fault system.