Savage, B., D. Dreger and J. Lynch , "Investigations into Historic California Seismicity: 1952 Kern Co. Sequence submitted to Fall 1996 AGU meeting in San Francisco
We have examined the paper record archive at UC Berkeley to search for seismograms of significant historic earthquakes of suitable quality for detailed waveform analysis. The selected events are first scanned and then digitized using the nxscan software distributed by IRIS. Once the preliminary data processing is completed it is then possible to analyze the seismograms using modern waveform modeling techniques. For the July 21, 1952 Kern Co. sequence (Mw7.3) we have identified 19 Mw>4.0 aftershocks with high quality three-component seismograms recorded by a Galitzen instrument. Although the mainshock and several of the larger aftershocks are clipped the smaller aftershocks have usable three-component waveforms which enable the determination of single station (BRK) moment tensor estimates. Thus far a variety of moment tensor solutions have been obtained for the aftershocks however the mechanisms are predominantly thrust with a San Andreas fault normal orientation Figure
. Our future plans are to include additional first-motion, regional waveform (Caltech) and teleseismic waveform data where available. In addition to the preliminary results we will present our sensitivity analysis of the single station inversions.