[en] A mathematical model has been developed which describes the influence of depth on recorded seismic ground motion. Comparison of the predicted transfer functions obtained from the model with actual field measurements indicates that the model performs reasonably well under a wide variety of complex geological conditions with varying physical properties. The model has been tested at five distinct sites at the NTS with the subsurface depth ranging from 200 to 2200 feet. No discernible performance deviation was detected as the subsurface depth was increased over this region. Although the comparisons deal exclusively with sites located within the NTS boundary, the results are equally applicable to other geographic regions being considered as potential waste isolation sites