NGA-East “Sigma” Workshop

NGA East logos of sponsors

“Sigma” Workshop
February 10, 2010; 9:30AM – 4:30PM
310 CITRIS Building (Sutardja Dai Hall), UC Berkeley

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.

The first of such public workshops is the “Sigma Workshop”, which will focus on issues related to the uncertainty in the ground motion prediction equations (GMPEs) for the central & eastern North-America (CENA). The goals of the workshop are to:

  • Identify the key technical issues to be resolved related to aleatory and epistemic uncertainties of GMPEs for CENA,
  • Provide a tentative plan to address the technical issues identified, and
  • Collect feedback from the workshop’s participants on the technical issues and tentative plan.

How can I attend this seminar?

  1. Attend in person at Auditorium in Room 310, Sutardja Dai Hall (CITRIS), UC Berkeley. Attending the workshop is free of charge; however, registration is required. Please register below before February 1, 2010.
  2. Watch remotely via Webcast live at 9 am February 10 2010: mms:// The webcast will become available at 8:45 am. It should load automatically, but if you have problems, make sure your computer has the latest version of Windows Media Player, RealPlayer or QuickTime installed. If you have questions during the webcast, email them to Yousef Bozorgnia ( and he will announce them during the Q&A period following each presentation.

We hope you can attend and look forward to your input. The detailed agenda of the workshop will be distributed in the following weeks.

Next Generation Attenuation for CENA ( NGA-East) “Sigma” Workshop

February 10, 2010

Attend in person at Auditorium in Room 310, Sutardja Dai Hall (CITRIS), UC Berkeley.

Agenda (PDF file – 2.1 MB)

Presentation Files

Videos of the workshop

Introduction, Sigma Public workshop Feb, 2010

Overview of NGA-East Program

Funding Agencies’ Perspective

Funding Agencies’ Perspective, speaker Larry Salomone

Sigma: What it is, Why it Matters and What Can We Do With It

Sigma in NGA-East: Framework, Terminology & Tentative List of Action Items

Sensitivity of Hazard to Sigma; and Hisorical Evolution of Sigma in CENA

Comparison of sigma for active regions and SCRs: EPRI 2006 Approach

Magnitude Dependence of Sigma: Preliminary Analysis of Small Magnitude Data

Sigma: Point Source Stress Drop Variablility – Example Estimation of Inter-Event Parametric Term

Quantification of Epistemic Uncertainty on Ground Motion Models

Constrainsts on Sigma from Physical Evidence

Sigma Closing Discussions

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