Document: NUREG-0800
Document ID: 91dd5605-fced-4aa9-82f4-b0def4175216
Document Type: srp
Title: Safe Shutdown Earthquake. In meeting the requirements of Ref-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340591.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.6
CFR Part: 
CFR Title: 

Content:
path, and site properties (e.g., Ref. 36). Sensitivity studies should show the effects of scaling. 3. If strong-motion records are not available, site-specific peak ground acceleration, velocity, and displacement (if necessary) should be deter- mined for appropriate magnitude, distance, and foundation conditions. Then response spectra may be determined by scaling the acceleration, velocity, and displacement.values by appropriate amplification factors (e.g., Ref. 37). Where only estimates of peak ground acceleration are available, it is acceptable to select-a peak acceleration and use this peak acceleration as the high frequency asymptote to standardized response spectra such as described in Regulatory Guide 1.60 (Ref. 6) for both the horizontal and vertical components of motion with the appropriate amplification factors. For each controlling earthquake, the peak ground motions should be determined using current relations between acceleration, velocity, and, if necessary, displacement, earth- quake size (magnitude or intensity), and source distance. Peak ground motion should be determined from state-of-the-art relationships. Rela- tionships between magnitude and ground motion are found, for example, 2.5.2-7 Rev. 2 - August 1989 in References 38, 39, 40, and 41 and relationships between ground motion and intensity are found, for example, in References 41, 42, and 43. Due to the limited data for high intensities greater than Modified Mercalli Intensity (MMI) VIII, the available empirical relationships between intensity and peak ground motion may not be suitable for determining the appropriate reference acceleration for seismic design. 4. Response spectra developed by theoretical-empirical modeling of ground motion may be used to supplement site-specific spectra if the input parameters and the appropriateness of the model are thoroughly docu- mented (e.g., Refs. 19, 44, 45 and 46). Modeling is particul arly useful for sites near capable faults that may experience