This project investigated the use of cone penetrometer test (CPT) data in the paleoseismic study of the Newport-Inglewood fault zone (NIFZ) in Orange County. Southern California. Existing paleoseismic techniques, such as trenching, can be very difficult or impractical in low lying areas with shallow ground water. CIT can be used to determine the properties of a soil and to profile the subsurface geology. The goals of this project were to correlate stratigraphy with existing CIT and boring data. These data would then be used to locate faults, and interpret the seismic history at this site. The CPT results show that units can be correlated and vertical displacement across faults can be measured. The results also show that with closer spacing of cone penetrometer tests better results can be obtained. This project was successful in meeting the preliminary goals and demonstrates that CPT borings can be a useful paleoseismic tool.