Limits on crustal differential stress in southern California from topography and earthquake focal mechanisms
Karen Luttrell, & Bridget Smith-KonterPublished July 22, 2017, SCEC Contribution #6064
The in situ crustal stress field fundamentally governs, and is affected by, the active tectonic processes of plate boundary regions, yet questions remain about the characteristics of this field and the implications for active faults in the upper crust. We estimate the magnitude of the non-lithostatic in situ stress field in southern California by balancing in situ orientation indicated by earthquake focal mechanisms against the stress imposed by topography, which tends to resist the motion of strike-slip faults. The model assumes modern topography represents a state of critical transition in the crust from elastic to perfectly plastic behavior. Our results, based on the most rugged topography along the San Andreas Fault System, indicate that differential stress at seismogenic depth must exceed 62 MPa, consistent with differential stress estimates from complimentary methods. This furthermore suggests pore pressure must be less than hydrostatic and that coefficient of friction cannot be very low.
Citation
Luttrell, K., & Smith-Konter, B. (2017). Limits on crustal differential stress in southern California from topography and earthquake focal mechanisms. Geophysical Journal International, 211(1), 472-482. doi: 10.1093/gji/ggx301.
Related Projects & Working Groups
Community Stress Model
