The concept that the "Calaveras fault" is a linear, continuous, right-lateral strike-slip fault in central California has no validity, based on detailed field data. The Calaveras Fault Zone is a valid concept. It is demonstrated, via a series of 40 serial cross sections across the zone from Fremont to Gilroy, that the Calaveras Fault Zone is composed of out-of-the-syncline faults, and rotated faults arising from the center of a compressed basin.

This Miocene basin has been almost completely destroyed by the Pleistocene-Holocene approach of a basement high against a pre-existing Diablo High. The area has been shortened by compressional forces alone.

Examination of other "strike-slip" faults in Central California, including the San Andreas, Hayward, Concord, Greenville, etc., faults demonstrates that the concept of strike-slip motion as a major factor in the tectonics of the region is in error, and must be abandoned