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:
hquake that could occur un der the current tectonic regime, and a complete descrip tion of the uncertainty. A typical model used for PSHA is the use of a truncated exponential model for the mag nitude distribution and a stationary Poisson process for the temporal and spatial occurrence of earthquakes. Seismic Source'- Seismic source is a general term re ferring to both seismogenic sources and capable tecton ic sources. Capable Tectonic Source - A capable tectonic source is a tectonic structure that can generate both vibratory ground motion and tectonic surface de formation such as faulting or folding at or near the earth's surface in the present seismotectonic re gime. It is described by at least one of the following characteristics: a. Presence. of surface or near-surfice deforma tion of landforms or geologic deposits of a re curring nature within the last approximately 500,000 years or at least once in the last approximately 50,000 years. b. A reasonable association with one or more moderate to large earthquakes or sustained earthquake activity that are usually accompa nied by significant surface deformation. c. A structural association with a capable tectonic source having characteristics of either section a or b in this paragraph such that movement on one could be reasonably expected to be accom panied by movement on the other. * In some cases, the geological evidence of past activity at or near the ground surface along a poten tial capable tectonic source may be obscured at a particular site. This might occur, for example, at a site having a deep overburden. For these cases, evi dence may exist elsewhere along the structure from which an evaluation of its characteristics in the vi cinity of the site can be reasonably based. Such evi dence is to be used in determining whether the structure is a capable tectonic source within this definition. Notwithstanding the foregoing paragraphs, the association of a structure with geological structures that are at least