Accelerograms—Parkfield earthquake

Abstract
Five accelerograms obtained during the main shock of the Parkfield earthquake series at locations adjacent to and within 10 miles of the trace of the San Andreas fault are presented together with limited analysis by electric analog methods. With one exception records from horizontal accelerometers are characterized by a short duration section of high acceleration. Adjacent to faulting an acceleration pulse of 0.5 gravity was recorded. Judged by a record from a station east of the fault on rock and a record from a station approximately the same distance west of the fault on alluvium, magnification of response spectra by alluvium was less than a factor of 3.