Geodetic determination of relative plate motion in central California

Abstract

Geodetic data along the San Andreas fault between Parkfield and San Francisco, California
\n(latitudes 36°N and 38°N, respectively), have been re-examined to estimate the current relative
\nmovement between the American and Pacific plates across the San Andreas fault system.
\nThe average relative right lateral motion is estimated to be 32 ± 5 mm/yr for the period
\n1907-1971. Between 36°N and 37°N it appears that most, if not all, of the plate motion is
\naccommodated by fault creep. Although strain is presumably accumulating north of 37°N
\n(San Francisco Bay area), the geodetic evidence for accumulation is not conclusive.