ML23073A371
| ML23073A371 | |
| Person / Time | |
|---|---|
| Issue date: | 03/23/2023 |
| From: | Louise Lund NRC/RES/DE |
| To: | Eric Benner Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML23073A369 | List: |
| References | |
| RIL 2023-03 | |
| Download: ML23073A371 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 23, 2023 MEMORANDUM TO: Eric Benner, Director Division of Engineering Office of Nuclear Reactor Regulation McKirgan, John signing on behalf FROM: Louise Lund, Director of Lund, Louise on 03/23/23 Division of Engineering Office of Nuclear Regulatory Research
SUBJECT:
UPCOMING PUBLICATION OF RESEARCH INFORMATION LETTER (RIL 2023-03) MAGNITUDE CONVERSION AND EARTHQUAKE RECURRENCE RATE MODELS FOR THE CENTRAL AND EASTERN UNITED STATES The Office of Nuclear Regulatory Research (RES) is providing the enclosed Research Information Letter (RIL) entitled Magnitude Conversion and Earthquake Recurrence Rate Models for the Central and Eastern United States for your information and use. The RIL (RIL 2023-03) is available in the Agencywide Documents Access and Management System (ADAMS) with an accession number of ML23073A370. It will be published publicly within the next two weeks.
This RIL has been developed as part of RES activities to assess factors that affect estimates of background seismicity rates (i.e., earthquakes that are not associated with mapped faults) in the Central and Eastern United States (CEUS). This study was performed in part because previous NRC sponsored studies indicated that background seismicity rates estimated through different approaches by the USGS, and the US NRC may be the cause of the discrepancies between the two agencies seismic hazards estimates in the CEUS. In this collaborative research, background seismicity rates at three locations in the CEUS estimated by the USGS and NRC models were compared. Although the distribution of seismicity rates was generally similar, the study found that differences in the distribution may result in differences in mean hazard estimates.
In addition, background seismicity rates were found to be affected by models used to convert local magnitudes of small earthquakes to moment magnitudes. This study explored avenues to mitigate the current effects of magnitude inconsistencies through targeted studies to develop magnitude conversion relationships with lower bias, particularly focused on small magnitudes.
Contact:
Rasool Anooshehpoor RES/DE/SGSEB 301-415-2396
E. Benner A draft version of this report was shared and reviewed with staff in NRR/DEX and all their comments were addressed.
RES has established an online quality survey to collect feedback from user offices on the usefulness of RES products and services. This survey can be found online at the hyperlink:
RES Quality Survey. I would appreciate the responsible manager completing this short survey within the next 10 working days to present your offices views of the delivered RES product.
Please share any concerns with me or the Division of Engineering contact listed, so that they may be addressed.
Enclosure:
RIL 2023-03, Magnitude Conversion and Earthquake Recurrence Rate Models for the Central and Eastern United States,
ML23073A3693; ML23073A371 OFFICE RES/DE/SGSEB RES/DE/SGSEB RES/DE LLund NAME AAnooshehpoor AA DSeber DS JMcKirgan for JM DATE Mar 15, 2023 Mar 15, 2023 Mar 23, 2023