Deformation at the lithosphere-asthenosphere boundary is strongly governed by its effective viscosity, which depends on temperature, strain rate, and grain size. Moreover, deformation can cause lattice preferred orientation resulting in seismic anisotropy and shear wave splitting. We used a 1D model approach to calculate shear strain and characteristic depths for an oceanic plate as a function of age. We assume a composite rheology (dislocation and diffusion creep) in combination with a half-space cooling model temperature field for constant and variable thermal parameters, and different potential mantle temperatures. Systematically, sensitivity of characteristic depths, deformation pattern, and seismic delay times δt on temperature, plate velocity, steady state grain size, and rheology have been analyzed. Model results show that the characteristic depths are only affected by local variations in the temperature field or a shift in the dominant deformation mechanism. The other parameters, however, do strongly affect the maximum total shear strain. Due to a continuous simple shear of the upper mantle governed by the motion of the plate, anisotropy, thickness of the anisotropic layer, and δt reach relatively large values in comparison to observed data. However, a small amount of dislocation creep (25-40 %), due to a modified rheology or small grain sizes, leads to a significantly thinner anisotropic layer. As a result, δt is reduced by 50 % or more. The change of the characteristics of the anisotropic layer and degree of its anisotropy may reflect and be of significance for the viscous (de)coupling between the lithosphere and asthenosphere.