Lithospheric Deformation Associated with Two-Dimensional Strike-Slip Faulting.

Abstract

To model the coseismic and postseismic lithospheric deformations associated with faulting at a transform plate boundary, the problem of a long inclined strike-slip fault in a layer overlying a uniform half-space is discussed. Closed-form expressions for the static displacements and stresses are obtained when the two media are elastic. These expressions are used to study the effect of the source location and the dip of the fault on the surface deformation. The correspondence principle of linear viscoelasticity is used to obtain the quasi-static field when the layer is elastic and the half-space Maxwell viscoelastic. The coseismic field is modeled by the static response and the postseismic field is modeled by the quasi-static response minus the static response. The variation of the coseismic and postseismic surface displacement and shear stress with the distance from an inclined fault is studied for four source locations: a surface-breaking fault and three buried faults. Both the source location and the dip of the fault are found to influence the deformation field significantly. Contours of constant postseismic displacement and stresses on the distance-time grid are obtained. These contours are useful in examining the spatial and temporal dependence of the displacement and stress fields. It is found that while the nodal lines for the postseismic displacement are independent of time, the nodal lines for the postseismic shear stresses move away from the fault with time after the earthquake.

Seismic cycle on a strike-slip fault with rate- and state-dependent strength in an elastic layer overlying a viscoelastic half-space

“…This is a good approximation, as shown by Singh and Rani (1994), because |F m | rapidly decreases with m for z and z smaller than h. The frictional stress τ on the fault is assumed to obey a composite rate-and state-dependent friction law proposed by Kato and Tullis (2001). This friction law was made by slightly modifying existing rate-and state-dependent friction laws (slip law and slowness law) originally developed by Dieterich (1979) and Ruina (1983) so that a wide range of experimental observations may be fitted.…”

Interaction of parallel strike-slip faults and a characteristic distance in the spatial distribution of active faults

“…The nth term in the in®nite series in eqs (2) and (4) represents a contribution to stress from image dislocations at z#tnh, and its magnitude rapidly decreases with increasing n. We approximate the in®nite series by taking the initial 100 terms; this is a very good approximation as shown by Bonafede et al (1984) and Singh & Rani (1994). The nth term in the in®nite series in eqs (2) and (4) represents a contribution to stress from image dislocations at z#tnh, and its magnitude rapidly decreases with increasing n. We approximate the in®nite series by taking the initial 100 terms; this is a very good approximation as shown by Bonafede et al (1984) and Singh & Rani (1994).…”

Non-planar fault models: complexities induced by crustal layering in transcurrent faulting processes

“…The integral kernels , for an elementary screw dislocation of arbitrary dip embedded in the upper layer are given by Singh & Rani (1994), while the kernels can be obtained using the analytical solutions proper to a vertical screw dislocation (Bonafede et al 2002). Once the stress drops Δσ 1 , Δσ 2 are assigned, the equilibrium equations become a system of coupled integral equations for the unknown functions ρ 1 , ρ 2 .…”