Data from a precision multi-wavelength distance measuring (MWDM) instrument, located near Hollister, California, have been analyzed in terms of strike-slip faulting in the region covered by the network. Four episodes of deformation that are readily identifiable in the MWDM data for the year following September 1975 can be modeled as slip on the Calaveras fault. Creepmeter data tend to support this interpretation, since the creep events and the observed episodes of deformation appear to be correlated in a temporal sense. Lower bounds on the moment for each episode of slip can be determined from the MWDM data by the technique of linear programing. The results indicate that aseismic slip is the dominant mechanism for strain release, since the combined moment of 1.16 x 1024 dyn cm for the four episodes far exceeds the moment of all of the earthquakes that occurred during the year. Creepmeter data and geologic evidence that are taken in conjunction with the lower bound of the moment indicate that the depth of aseismic slip for some of the episodes of fault slip could extend to below the greatest depth of earthquake hypocenters for this region of central California. -Author
Additional Publication Details
An interpretation of episodic slip on the Calaveras fault near Hollister, California.