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:
the ground motion lev el for the I and 2.5 Hz and the 5 and 10 Hz spectral ac celeration pairs. Step 3 Perform a complete probabilistic seismic hazard analysis for each of the magnitude-distance bins illustrated in Table C.1. (These magnitude-distance bins are to be used in conjunction with the LLNL or EPRI methods. For other situations, other binning schemes may be necessary.) Table CA Recommended Magnitude and Distance Bins Magnitude Range of Bin Distance Range " of Bin (kn) 5-5.5 5.5-6 6-6.5 6.5-7 >7 0-15 15-25 25-50 50-100 100-200 200 -300 >300 1.165-17 Step 4 From the de-aggregated results of Step 3, the me dian annual probability of exceeding the ground mo tion levels of Step 2(a) (spectral accelerations at 1, 2.5, 5, and 10 Hz) are determined for each magnitude distance bin. These values are denoted by Hmdf. Using Hmdf values, the fractional contribution of each magnitude and distance bin to the total hazard for the average of 1 and 2.5 Hz, P(m,d)1, is computed ac cording to: (>.lmHf) - 2 Equation (1) 2 rM d where f =1 and f =2 represent the ground motion measure at 1 and 2.5 Hz, respectively. The fractional contribution of each magnitude and distance bin to the total hazard for the average of 5 and 10 Hz, P(md)2, is computed according to: 2 d 2 p 4 Equation (2) where f = I and f = 2 represent the ground motion measure at 5 and 10 Hz, respectively. Step S Review the magnitude-distance distribution for the average of 1 and 2.5 Hz to determine whether the con tribution to the hazard for distances of 100 km or great er is substantial (on the order of 5% or greater). If the contribution to the hazard for distances of 100 km or greater exceeds 5%, additional calculations are needed to determine the controlling earthquakes us ing the magnitude-distance distribution for 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