Jennifer L. Hatch, Michele Lynn Cooke, Hanna Marie Elston

Crustal deformation models show incompatibility between inferred fault geometry and geologic slip rates where model and geologic slip rates disagree. We do not know if the impact of these incompatibilities is local to sites or has wider effect on the fault system deformation. Here, we investigate the roles of structural position of sites and uncertainty of slip rates using one suite of mechanical models that limits the dextral slip rates to within the range of observed slip rates at the sites of geologic investigations and another suite that explores the impact of each slip rate site on each other and on the nearby fault system. The suites of models employ two viable configurations for the southern San Andreas fault: with and without an active northern slip pathway around the San Gorgonio Pass. The Active Northern Pathway model has slighter greater mismatch to young geologic slip rates than the Inactive Northern Pathway model but both are plausible. The impact of strike-slip rate sites on the system depends on their structural positions. Sites along short and segmented faults may have lesser impact on the system than either sites along longer faults or sites at fault branches. Consequently, inaccuracies in the slip rates used for seismic hazard assessment may have differing impacts depending on location of the slip rates. Fault branches along strike-slip faults warrant detailed investigation because these areas have high spatial variability of slip rate and accrue nearby off-fault deformation, affecting our ability to accurately assess seismic hazard of the region.