Document: NUREG-0800
Document ID: 13b10142-e3b6-4311-85bb-b56ed9bccf07
Document Type: srp
Title: Seismic Wave Transmission Characteristics of the Site.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340591.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.5
CFR Part: 
CFR Title: 

Content:
In meeting the requirements of Reference 1, this subsection is accepted when the seismic wave transmission characteristics (amplification or deamplifica- tion) of the materials overlying bedrock at the site are described as a function of the significant frequencies. The following material properties should be determined for each stratum under the site: seismic compressional and shear wave velocities, bulk densities, soil index properties and classifi- cation, shear modulus and damping variations with strain level, and water table elevation and its variation. 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. For the maximum earthquake, determined in Subsection 2.5.2.4, the free-field ground motion (including significant frequencies) must be determined, and an analysis should be performed to determine the site effects on different seismic wave types in the significant frequency bands. If appropriate, the analysis should consider the effects of site conditions and material property variations upon wave propagation and frequency content. 2.5.2-5 Rev. 2 - August 1989 The free-field ground motion (also referred to as control motion) should be defined to be on a ground surface and should be based on data obtained in the free field. Two cases are identified depending on the soil characteris- tics at the site and subject to availability of appropriate recorded ground- motion data. When data are available, for example, for relatively uniform sites of soil or rock with smooth variation of properties with depth, the control point (location at which the control motion is applied) should be specified on the soil surface at the top of the finished grade. The free- field ground motion or control motion should be consistent with the properties of the soil profile. For sites composed of one or more thin soil layers overlying a competent material, or in case of insufficient recorded