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:
r distances greater than 100 km (63 mi). This distribution, P>loo(md)l, is defined by: P > 100 (m, d), = P(m9d) 1 m d>100 Equation (3) The purpose of this calculation is to identify a dis tant, larger event that may control low-frequency con tent of a response spectrum. The distance of 100 km is chosen for CEUS sites. However, for all sites the results of full magnitude distance distribution should be carefully examined to ensure that proper controlling earthquakes are clearly identified. Step 6 Calculate the mean magnitude and distance of the controlling earthquake associated with the ground motions determined in Step 2 for the average of 5 and 10 Hz. The following relation is used to calculate the mean magnitude using results of the entire magnitude distance bins matrix: Me(5-10Hz) = >mEjP(md), m d Equation (4) where m is the central magnitude value for each magnitude bin. The mean distance of the controlling earthquake is determined using results of the entire magnitude distance bins matrix: Ln{D.(5-10Hz)} = >jLn(d)>jP(md)2 d m Equation (5) where d is the centroid distance value for each dis tance bin. Step 7 If the contribution to the hazard calculated in Step 5 for distances of 100 km or greater exceeds 5% for the average of 1 and 2.5 Hz, calculate the mean magnitude and distance of the controlling earthquakes associated with the ground motions determined in Step 2 for the average of 1 and 2.5 Hz. The following relation is used to calculate the mean magnitude using calculations based on magnitude-distance bins greater than dis tances of 100 km as discussed in Step 4: M. (1 - 2.5 Hz) M rn P > 100 (m, d) M d>100 Equation (6) where m is the central magnitude value for each magnitude bin. The mean distance of the controlling earthquake is based on magnitude-distance bins greater than distances of 100 km as discussed in Step 4 and deter mined according to: 1.165-18 I-. P(M, d)2 Ln {D,(1 - 2.5 Hz)} = Ln(d) P > 100(m,d), d>10 ., Equation (7) where d is the centroid