| Very few data are available regarding the recurrence interval and behavior of the Peninsula segment of the San Andreas Fault. Additional data are required to accurately describe the history and characteristics of slip on the fault. Trenching perpendicular across the fault in Portola Valley, California has provided insight into the timing of surface rupture earthquake events (such as the April 18, 1906 earthquake).;The trench revealed scarp-derived colluvial wedges that overlie and interfinger with Holocene fluvial deposits. The data indicate an average recurrence interval of approximately 292 years and a penultimate event date of 1400 A.D. or later. These data correlate well with data from previous studies that show a penultimate 1906-type earthquake on the northern section of the SAF occurring between 1655 and 1588. |
