Interpreting GPS data from a transect across the Pacific-North America plate boundary, passing through the San Bernardino Mountains

Event Center A & B

Through GPS research I have obtained probable slip rates for ten faults within a transect across the Pacific-North America plate boundary passing through the San Bernardino Mountains. These slip rates were estimated by using an Excel Macro to compare the observed deformation profile to what would be predicted from elastic theory for various rates of fault slip in the lower crust. This model yielded best fit slip rates for the faults studied as follows: San Clemente Fault, 3mm/yr; Palos Verdes Fault, 2mm/yr; NewportInglewood Fault, 4mm/yr; Elsinore Fault, 3mm/yr; San Jacinto Fault, 10mm/yr; San Andreas Fault, 10mm/ yr; Helendale Fault, 0mm/yr; Lenwood Fault, 1mm/yr; Calico, 12mm/yr; and Ludlow Fault, 1mm/yr. There is a large uncertainty in the slip rate of San Andreas Fault (SAF). Although the best fitting model has a SAF rate of 10mm/yr, models with an SAF rate as low as 2mm/ yr or as high as 18mm/yr fit the observed profile of site velocities relatively well.