The Coyote Lake earthquake (ML = 5.9; August 6, 1979; epicenter about 100 km southeast of San Francisco) occurred on the Calaveras fault within a geodetic network that had been surveyed annually since 1972 to monitor strain accumulation. The rupture surface as defined by aftershocks is a vertical rectangle 20 km in length extending from a depth of 4 km to about 12 km. The observed deformation of the geodetic network constrains the average slip to be about 0.33¿0.05 m right lateral. Although the geodetic data furnished an exceptionally detailed picture of the preearthquake deformation, no significant premonitory anomaly associated with the Coyote Lake earthquake can be identifited.