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:
based on increasing the amount of detailed information as they proceed from the regional level down to the site area (e.g., 320 km to 8 km distance from the site). Whenever faults or other structures are encountered at a site (including sites in the CEUS) in either outcrop or excavations, it is necessary to perform many of the in vestigations described below to determine whether or not they are capable tectonic sources. The investigations for determining seismic sources should be carried out at three levels, with areas de scribedby radii of 320 km (200 mi), 40 km (25 mi), and 8 km (5 mi) from the site. The level of detail increases closer to the site. The specific site, to a distance of at least 1 km (0.6 mi), should be investigated in more de tail than the other levels. The regional investigations [within a radius of 320 *km (200 mi) of the site] should be planned to identify seismic sources and describe the Quaternary tectonic regime. The data should be presented at a scale of 1:500,000 or smaller. The investigations are not ex pected to be extensive or in detail, but should include a comprehensive literature review supplemented by fo cused geological reconnaissances based on the results of the literature study (including topographic, geologic, aeromagnetic, and gravity maps, and airphotos). Some detailed investigations at specific locations within the region may be necessary if potential capable tectonic sources, or seismogenic sources that may be significant for determining the safe shutdown earthquake ground motion, are identified. The large size of the area for the regional investiga tions is recommended because of the possibility that all significant seismic sources, or alternative configura tions, may not have been enveloped by the LLNL/EPRI data base. Thus, it will increase the chances of (1) iden tifying evidence for unknown seismic sources that might extend close enough for earthquake ground mo tions generated by that source to affect the site and (2)