Limits on crustal differential stress in southern California from topography and earthquake focal mechanisms

作者：Luttrell Karen; Smith Konter Bridget

来源：Geophysical Journal International, 2017, 211(1): 472-482.

DOI：10.1093/gji/ggx301

• Numerical approximations and analysis
• Spatial analysis
• Seismicity and tectonics
• Continental tectonics: strike-slip and transform
• Mechanics, theory and modelling

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 differential stress at seismogenic depth 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. Our results indicate that most regions require differential stress of at least 20 MPa at seismogenic depth. In the areas of most rugged topography along the San Andreas Fault System, 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 lithostatic and that coefficient of friction cannot be very low (i.e. coefficient of static friction > 0.3).

• 出版日期2017-10