Lateral strain modulation in a Si substrate arising from laterally patterned periodic SiO2 stripes were investigated by x-ray grazing incidence diffraction. In this diffraction geometry a depth dependent in-plane strain analysis was performed. Using finite element calculations the displacement field in the non-patterned Si substrate was calculated, which served as an input for the simulation of the diffracted intensities based on the distorted-wave Born approximation. By varying the lattice mismatch between the SiO2 stripes and the substrate, a good agreement between simulations and experimental diffraction data could be achieved.