Photomosaics and logs of trenches on the San Andreas Fault at Arano Flat near Watsonville, California

We present photomosaics and logs of the walls of trenches excavated for a paleoseismic
study at Arano Flat, one of two sites along the San Andreas fault in the Santa Cruz Mountains
on the Kelley-Thompson Ranch. At this location, the fault consists of a narrow
zone along the northeast side of a low ridge adjacent to a possible sag pond and extends about
60-70 meters across a broad alluvial flat. This site was a part of Rancho Salsipuedes beginning
in 1834 and was purchased by the present owner’s family in 1851.