This document describes the calculations performed to develop updated relative amplification functions for the Waste Treatment and Immobilization Plant (WTP) facility at the DOE Hanford Site, Washington State. The original 2,000-year return period design spectra for the WTP were based on the results of a probabilistic seismic hazard analysis (PSHA) performed for the DOE Hanford Site by Geomatrix (1996). Geomatrix (1996) performed the PSHA using empirical soil-site ground motion models based primarily on recordings from California. As part of that study, site response analyses were performed to evaluate ground motions at the Hanford sites and California deep soil sites. As described in Appendix A of Geomatrix (1996), characteristic site profiles and dynamic soil properties representative of conditions at various Hanford sites and California deep soil strong motion recording stations were defined. Relative site responses of the Hanford profiles and California profiles were then compared. Based on the results of those site response analyses, it was concluded that ground motions at the Hanford sites underlain by deep soil deposits are similar in character to those on California deep soil sites and it was judged appropriate to use empirical deep soil site attenuation relationships based primarily on California ground motion data to develop design spectra for the Hanford sites. In a subsequent analysis, Geomatrix (2003) updated the site response analyses of Geomatrix (1996, Appendix A) to incorporate randomization of the California and Hanford profiles.