Physical modelling of transpressional strike-slip faulting: Implications for deformational styles surrounding the San Andreas fault zone.

摘要

Thrust faults and folds parallel to the central and northern portions of the San Andreas fault zone are not consistent with the expected orientation of deformational features stemming from a high friction, coupled, pure right-lateral strike-slip fault.;The genetic relationship between compressional subsurface faulting and surface folding surrounding the San Andreas fault has important implications for seismic hazard zonation. The ability to recognize potentially hazardous compressive stress regimes is enhanced through the use of this modelling study.;Physical modelling of the San Andreas fault zone, in this study, incorporates the most recent stress field, fault zone, and plate motion data that suggest the San Andreas fault zone is a low-friction, decoupled, transpressional fault zone. Gelatin modelling experiments indicate that fault-parallel thrust faults and folds are related to the convergent component of transpression acting perpendicular to the model plate boundary. Sand models indicate that deformation occurs along low-angle detachment faults in response to fault-normal maximum horizontal stress. The correlation of gelatin and sand models is consistent with observed deformation along the central and northern portions of the San Andreas fault zone.