NGA-East Tentative Plan March 7, 2008
Brainstorming Technical Workshop in 2007 To compile a list of key technical issues and R&D projects to be addressed in the course of NGA-East The list was finalized through iterations Consensus was to develop Next Generation Models rather than updating PSHA implementation of the existing models Very short summary of topics…
Supporting R&D Topics for NGA-East: 1 Database: Compile a database of recorded motions from CEUS and other Stable Continental Regions (SCR) Data will be processed uniformly, reviewed, and QA’d PGA, PGV, PGD, and response spectra for periods 0.01 to 10 sec
Database metadata should include: Database (cont’d) Database metadata should include: Moment magnitude for all EQs Rupture, JB, epicental and hypocentral distances Vs30 and basin/sediment depth estimates at recording stations … In order to save time, for short term, a working group on database is formed
Topic 2 Source Rupture Characterization: Source parameter database: Rupture area, moment, … Compare source characteristics of EQs in magnitude range of 4-5 from WUS to CEUS: Any difference? Why? …
Topic 3 Source-Site Path: Geometrical spreading effects: What is the physical cause for a geometrical spreading steeper than 1/R? Are there differences for geometrical spreading between WUS and CEUS? …
Topic 4 Site Effects: Define a reference site condition to use in the development of the attenuation models for CEUS Are site-response effects transferable from WUS to CEUS? …
Topic 5 Constraints on Attenuation Models: Develop and use MMI distributions for CEUS and other SCR earthquakes to constrain and check spectral levels for large magnitudes Collect and analyze liquefaction data to constrain predicted spectral ordinates …
Topic 6 Ground Motion (GM) Simulation Calibrate & validate GM simulation models using CEUS and other SCR data Use calibrated and validated simulation models to generate GMs to be used by attenuation modelers (for a range of magnitude, distances, …) …
Topic 7 Modeling Issues for Attenuation Next generation attenuation models for CEUS should be applicable to magnitude 4-8, distances of 500km Horizontal and Vertical components Demonstrate agreement of new models with observed data in CEUS and other SCRs Develop aleatory uncertainty models for CEUS (function of magnitude, distance, …)
Topic 8 Implementation of Attenuation Models for PSHA Develop an epistemic uncertainty model Determine weights to be assigned to the new attenuation models …
Topic 9 Other Related (but out of scope) Project Develop VS30 and depth to bedrock maps for CEUS
Duration & Budget Final models ready to be reviewed by various stakeholders (including USGS): In Five years One year to review, collect comments, adopt for various applications (including National Seismic Hazard Maps) Estimated overall budget: $4.4M (including database, supporting R&D projects, attenuation models,…)
Timeline
Fully Transparent Process During the course of NGA-East program, the database developers, attenuation modelers, researchers, stakeholders and end-users of models will all be involved in a multi-disciplinary and fully transparent process
Fully Transparent Process The compiled database along with its documentations will be available to the public via an NGA-East web site The reports on the supporting research projects will be also available to the public
Fully Transparent Process For each attenuation model, there will be draft and final reports to document modeling development, assumptions, derivations, etc. Reports will be electronically available to the public free of charge
We would like to invite you to join NGA-East As a co-sponsor: Various organizations will benefit from NGA-East: NRC, USGS, DOE, NEHRP, other Federal Agencies,…private industry, utilities,… Be part of Joint Management Committee (JMC) to direct the program Be involved in various technical activities: Technical working groups; Workshops Supporting R&D projects
Discussions…