Document: NUREG-0800
Document ID: 126fcd17-2105-4867-bab4-804770e037d2
Document Type: srp
Title: Seismic Wave Transmission Characteristics of the Site.  In the PSHA procedure
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730593.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.5
CFR Part: 
CFR Title: 

Content:
described in Regulatory Guide 1.165, the controlling earthquakes are determined for generic rock conditions. Site amplification studies are performed in a distinct separate step as a part of the determination of the GMRS. In this section, the applicant's site 2.5.2-9 Revision 4 - March 2007 amplification studies are reviewed in conjunction with the geotechnical and structural engineering reviews. Particular emphasis is placed on how the uncertainties inherent in this process are addressed. To meet the requirements of 10 CFR 100.23, this subsection is acceptable when adequate information is provided to demonstrate that the site response analysis adequately estimates both the mean and variability of the site response in accordance with Regulatory Position 4 and Appendix E of Regulatory Guide 1.208. To be acceptable, the seismic wave transmission characteristics (amplification or deamplification) of the materials overlying bedrock at the site are described as a function of the significant frequencies (Ref. 11). The following material properties should be determined for each stratum under the site: thickness, seismic compressional and shear wave velocities, bulk densities, soil index properties and classification, shear modulus and damping variations with strain level, and the water table elevation and its variations (Ref. 15). In each case, methods used to determine the properties should be described in Subsection 2.5.4 of the SAR and cross-referenced in this subsection. Where vertically propagating shear waves may produce the maximum ground motion, a one-dimensional equivalent-linear analysis or nonlinear analysis may be appropriate and is reviewed in conjunction with geotechnical and structural engineering. However, site characteristics (such as a dipping bedrock surface, topographic effects or other impedance boundaries) may require that analyses are also able to account for inclined waves. The staff will review the ground motions developed for each of the