MATHEMATICAL BLOCK-MOTION MODEL FOR DEFORMATION OF A LAYER ABOVE A BURIED FAULT OF ARBITRARY DIP AND SENSE OF SLIP

An analytic series solution is obtained for the stress and deformation in an isotropic viscous, or incompressible elastic layer subjected to rigid-block motion at its base. The block motion approximates slip on a pre-existing basement fault of arbitrary dip and sense of slip. Deformation in the layer due to horizontally-separating and horizontally-converging blocks, slip on a vertical basement fault, and slip on 45 degrees-dipping reverse and normal basement faults is examined. Above horizontally-diverging and -converging blocks, a symmetric syncline and anticline form, respectively. Monoclines form above dipping basement faults. The location of the monocline, and to a lesser degree its form, vary systematically with fault attitude and sense of slip. For a given fault displacement, the region of brittle failure in a basement normal-fault model is larger than that in a reverse-fault model. New faults formed in the layer are arcuate in profile. Model results agree with observations of stress orientation and deformation from laboratory models.