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 (cont’d)
Database metadata should include:
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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:
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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:
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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:
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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:
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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
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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
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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
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Develop an epistemic uncertainty
model
Determine weights to be assigned to
the new attenuation models
…
Topic 9
Other Related (but out of
scope) Project
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Develop VS30 and depth to bedrock
maps for CEUS
Duration & Budget
Final models ready to be reviewed by
various stakeholders (including USGS):
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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
Database (including contingency)
R&D Supporting Projects (including
contingency)
GMPE Modelers: Initial involvement
& modeling phase
Review, QA, Workshops, Adoption
0
1
2
3
4
5
6
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 multidisciplinary 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:
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Various organizations will benefit from NGA-East:
 NRC, USGS, DOE, NEHRP, other Federal
Agencies,…private industry, utilities,…
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Be part of Joint Management Committee (JMC)
to direct the program
Be involved in various technical activities:
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Technical working groups; Workshops
Supporting R&D projects
Discussions…