NGA-East SSHAC Workshop 2, Oct. 11-13 2011

 

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Next Generation Attenuation for CENA (NGA-East)

SSHAC Workshop 2 – Proponent Discussions and Remaining Critical Issues and Data Needs

October 11-13, 2011

Agenda

With funding from the US Nuclear Regulatory Commission (NRC), Electric Power Research Institute (EPRI) and US Department of Energy, the Pacific Earthquake Engineering Research Center (PEER) is coordinating a comprehensive multidisciplinary program to develop Next Generation Attenuation Relationships for the Central and Eastern North-America (NGA-East).

As part of this research program, PEER will coordinate a large number of public workshops over the life of the project. The purposes of such workshops are to collect feedback from the earthquake community and inform the participants about the on-going technical activities. NGA East is treated as a SSHAC (Senior Seismic Hazard Analysis Committee) Level 3 program. See the Open-File Report 2009-1093 (PDF file – 992 KB) for a summary of the SSHAC process.

This is the second of several SSHAC Workshops.

Workshop Attendance

Over 75 participants attended the workshop free of charge at the Shattuck Plaza Hotel. An average of 25 participants attended virtually via PEER’s live video conferencing service, where participants could watch the presentations on their personal computer while hearing the presenter and discussion period via telephone. This virtual service was provided free of charge to attendees participating from both international and US locations.

PDFs of all presentations & videos

October 11, 2011 (8:00-12:00) NGA-East Project Plan and Remaining Critical Issues
View the video of this Oct 11 morning session on YouTube - before the break
View the video of this Oct 11 morning session on YouTube - after the break

8:00-8:15 Welcoming remarks, introduction to NGA-East and the project team (Y. Bozorgnia)
8:15-8:30 Sponsors perspective (A. Kammerer, S. McDuffie, L. Salomone)
8:30-9:15 Workshop scope and functioning, overview of SSHAC process and roles, Overview of the project plan (Figure 1) and progress since Workshop 1 (C. Goulet)
9:15-10:00 Overview of TI team approach to address remaining critical issues with hazard feedback analyses (TI team)
10:00-10:15 Break
10:15-11:15 Hazard feedback analyses using initial sensitivity models and a simplified CEUS SSC model (N. Abrahamson)
11:15-12:00 Discussion on remaining issues and plan devised to address them. Have we missed anything big?

October 11, 2011 (1:00-5:00) Earthquake Record Databases, Reference Rock and Removing Site Effects at Recording Stations
View the video of this Oct 11 afternoon session on YouTube - before the break
View the video of this Oct 11 afternoon session on YouTube - after the break before power outage
View the video of this Oct 11 afternoon session on YouTube - after the break after power outage

1:00-1:45 Review of final databases for CENA and other SCRs (C. Mueller/C. Cramer, G. Toro)
1:45-2:15 Ground motions from the Virginia earthquake and its aftershocks. What do the preliminary results imply for ground motions and hazard? How does this event compare to previous ones (e.g. Saguenay)? (G. Atkinson, J. Boatwright)
2:15-2:30 Discussion: Are the data collected sufficient? How will the data from other SCRs be used? Which remaining or additional data sets should be pursued?
2:30-3:00 Presentation on final proposed reference rock Vs and Kappa (Y. Hashash)
3:00-3:15 Break
3:15-4:00 Proponent presentations on “simple” models for correcting recorded motions to reference rock conditions (A. Kottke/Y. Hashash, E. Thompson/W. Silva)
4:00-4:30 Discussion on reference rock and correction: Is a change in reference Vs warranted? How will the corrected motions be used? Are the corrections adequate for that use?
4:30-5:00 Summary of the day (N. Abrahamson)

October 12, 2011 (8:00-12:00) Regionalization for Q, geometrical spreading and duration and for crustal Vs
View the video of this Oct 12 morning session on YouTube - before the break
View the video of this Oct 12 morning session on YouTube - after the break

8:00-8:15 Review of how the regionalization will be used (R. Graves)
8:15-9:15 Presentation of preliminary alternative 1D crustal models for CENA and proposed use of 1D crustal models in forward simulations (S. Detweiler/W. Mooney)
9:15-10:00 Presentation of the Path/Source WG preliminary attenuation regionalization model (M. Chapman)
10:00-10:15 Break
10:15-10:30 Regionalization and stress drop and the issue of spectral shape in CENA (J. Boatwright)
10:15-10:30 Review of hazard feedback analyses for sensitivity to attenuation parameters, overview of TI team approach for selecting final regions and summary of existing models and data to constrain attenuation (N. Abrahamson)
10:45-12:00 Discussion on regionalization with potential for significant impact on hazard. Do the proposed approaches cover the range of interpretation? Do proposed regional differences lead to large enough differences in hazard to justify potential model complexity? Can an increase in sigma cover the effect of regional differences? Are there additional data or approach that should be considered? How about the shallow profile to Vs=2.8-3.0 km/s

October 12, 2011 (1:00-5:00) Median GMPE Approaches, Testing of GMPEs and Standard Deviation (Sigma) Models
View the video of this Oct 12 afternoon session on YouTube - before the break
View the video of this Oct 12 afternoon session on YouTube - after the break

1:00-1:30 Introduction (R. Youngs)
1:30-2:30 Proponent discussion on GMPE approaches (point source stochastic, hybrid, and empirical) and their development. What methods, assumptions and approaches should be considered for extrapolation of results at large M? Is the stochastic approach flexible enough to capture finite fault effects? What range of GMPE approaches is needed to appropriately capture uncertainty in ground motions? (B. Darragh/W. Silva, K. Campbell, S. Pezeshk, P. Renault, G. Atkinson)
2:30-3:00 Discussion of critical issues for testing of GMPEs (TI team)
3:00-3:15 Break
3:15-3:30 Presentation of Sigma WG: hazard sensitivity to sigma models and approaches (L. Al Atik)
3:30-4:00 Presentation of alternative single-station sigma models from Swiss study (A. Rodriguez-Marek)
4:00-4:45 Discussion on available data and models that can be used to evaluate the sigma models.  Do the existing set of Sigma models capture the range of interpretation from the available data? (TI team)
4:45-5:00 Summary of the day (N. Abrahamson)

October 13, 2011 (8:00-12:00) Finite-fault simulations, models, validation and forward simulations
View the video of this Oct 13 morning session on YouTube - before the break
View the video of this Oct 13 morning session on YouTube - after the break

8:00-8:10 Introduction (C. Goulet)
8:10-8:45 Overview of finite-fault simulation validation protocol (R. Archuleta)
8:45-10:00 Presentation of model validation results by modelers (J. Bayless/P. Somerville, K. Olsen, A. Bykovstev, R. ArchuletaB. Darragh/W. Silva)
10:00-10:15 Break
10:15-11:15 Summary of additional FF methods to consider (TI team). Proponent discussion on FF methods strengths and weaknesses. Which FF methods better capture near field effects? Which set of methods collectively capture the range of uncertainty for forward simulations? What are the benefits and drawbacks of methods with a larger number of event-specific parameters?
11:15-11:45 Presentation and proponent discussion on M-A relationships for CENA (P. Somerville)
11:45-12:00 Discussion on M-A relationships. Are there additional datasets or approaches that need to be considered?

October 13, 2011 (1:00-4:00) Community distribution for input to finite fault and point source simulations
View the video of this Oct 13 afternoon session on YouTube - before the break
View the video of this Oct 13 afternoon session on YouTube - after the break

1:00-1:45 Discussion on community distribution (center, body and range) for input to finite fault simulations, with emphasis on correlation of parameters (R. Archuleta, R. Graves, S.G. Song)
1:45-2:00 Ground motion sensitivity to point source parameters, including 1 vs. 2 corners, Gs and Q, etc. Proposed methods for constraining point source model parameters and testing the resulting GMPEs for all M. Can we infer Ds for large M from small M data in a given region (examples from Switzerland and Southern/Central California)? (TI team)
2:00-2:15 Presentation of kappa scaling issues (L. Al Atik)
2:15-2:30 Development of alternative point-source simulation methods and review of critical issues (TI team)
2:30-2:45 Break
2:45-3:30 Discussion on community distribution (center, body and range) for point source model parameters based on technical basis and input developed by working groups (N. Abrahamson, A.M. Baltay).
3:30-4:00 Summary of the day (N. Abrahamson) and review of summaries for two previous days (TI team)
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