Analysis of stream offset along the San Gregorio fault zone, San Mateo County, California

The onshore San Gregorio fault near Ano Nuevo displays several stream deflections, possibly indicating recent fault movement. The objective of this study is to determine if calculating the correlation coefficient of several drainage basin volumes across the fault zone can identify dextrally offset streams. If dextral slip has separated the lower drainages from their original headwaters, low correlation coefficients are expected. Restoration of lower drainages to their original position is expected to produce higher correlation coefficients.;A weak, positive correlation of streams in their present spatial configuration, a slow (1--5 mm/yr) rate of modern stream offset, and the small (<1km) offset calculated for successfully restored streams, seem to negate the possibility of rapid Holocene fault movement. Streams north of Whitehouse Creek appear to be older than those to the south. However, stream development does not appear to progress uniformly from north to south, possibly due to the strike slip.