GEODOLITE MEASUREMENTS OF DEFORMATION NEAR HOLLISTER, CALIFORNIA, 1971-1978

A 24-station trilateration network spanning the San Andreas and Calaveras faults near Hollister, California, has been surveyed each year between 1971 and 1978, inclusive. Two moderate (ML equals 5) earthquakes have occurred within the network during the interval. No convincing preseismic or coseismic anomalies associated with those earthquakes have been identified. The deformation of the network can be described roughly by rigid body motion of the three blocks bounded by the two faults with accommodation occurring by right-lateral strike slip on the San Andreas (13 +- 2 mm/a) and Calaveras (17 +- 2 mm/a) faults.-Authors