Document: NRC Regulatory Guide
Document ID: cfc61809-5745-460f-8a26-13c168659924
Document Type: regulatory_guide
Title: Identification and Characterization of Seismic Sources and Determination of Safe Shutdown Earthquake Ground Motion
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740084.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.165
CFR Part: 
CFR Title: 

Content:
low and in Appen dix D of this guide may be used if additional seismic sources are to be developed as a result of investigations. 2.2 When the LLNL and EPRI methods are not used or are not applicable, the guidance in Regulatory Position 2.3 should be used for identification and char acterization of seismic sources. The uncertainties in the characterization of seismic sources should be ad dressed as appropriate. Seismic source is a general term referring to both seismogenic sources and capable tec tonic sources. The main distinction between these two types of seismic sources is that a seismogenic source would not cause surface displacement, but a capable tectonic source causes surface or near-surface displace ment. Identification and characterization of seismic sources should be based on regional and site geological and geophysical data, historical and instrumental seis micity data, the regional stress field, and geological ev idence of prehistoric earthquakes. Investigations to identify seismic sources are described in Appendix D. The bases for the identification of seismic sources should be documented. A general list of characteristics to be evaluated for a seismic source is presented in Ap pendix D. S2.3 -As part of the seismic source pharacteriza tion, the seismic potential for each source should be evaluated. Typically, characterization of the seismic potential consists of four equally important elements: 1. Selection of a model for the spatial distribution of earthquakes in a source. 2. Selection of a model for the temporal distribution of earthquakes in a source. 3. Selection of a model for the relative frequency of earthquakes of various magnitudes, including an estimate for the largest earthquake that could oc cur in the source under the current tectonic regime. 4. A complete description of the uncertainty. For example, in the LLNL study a truncated expo nential model was used for the distribution of magni tudes given that an earthquake has occurred in a