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.