Major Ongoing Ground Motion
Research Programs at PEER
Yousef Bozorgnia, Ph.D., P.E.
PEER, University of California, Berkeley
PEER is coordinating three major ground
motion programs
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Next Generation Attenuation (NGA)
relationships for Central & Eastern:
NGA-East
Follow-up studies of ground motion
prediction equations (GMPEs) for
shallow crustal earthquakes in active
tectonic regions: NGA-West 2
Global GMPEs for Global Earthquake
Model (GEM)
NGA- East
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Goal: To develop next
generation Ground
Motion Prediction
Equations (GMPEs)
for Central & Eastern
US
Stable Continental
Regions (SCRs)
Sponsors: NRC, EPRI,
USGS, DOE
How the Project was
Planned
Brainstorming Technical Workshops in
2007-2008
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Two invitational and a pubic workshops
Compiled 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
NGA-East Technical
Working Groups
Working Groups
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Database:
Compile a database of recorded motions
from CEUS and other Stable Continental
Regions (SCRs)
Geoetchnical Engineering:
Linear and nonlinear site responses; reference
rock condition,…
Working Groups
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Source-Site Path: Investigate
geometrical spreading steeper than 1/R;
Q; …
Ground Motion Simulation: Generate
calibrated & validated simulated GMs for
CEUS to be used by GMPE developers
Working Groups
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Sigma: To develop uncertainty models
for GMPEs. It is a joint WG between
NGA-East and NGA-West 2
Vertical Ground Motion: To
recommend development of vertical
GMPEs for CEUS, possibly by taking
advantage of empirical data for V/H, …
Working Groups
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GMPE Development
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Next generation attenuation models for
CEUS; applicable to magnitude 4-8,
distances of 0-1000 km
5% damped response spectra at periods
0.01 to 10 sec
NGA-East is a SSHAC Level 3 Project
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SSHAC (Senior Seismic Hazard
Analysis Committee) is a process:
To ensure fully transparent project
To ensure high quality research and
final product
Consistent with other related nuclear
projects by NRC, EPRI, DOE,…
Project Schedule
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Draft GMPEs to be ready for internal
(SSHAC) review:
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GMPEs to be ready for review by various
stakeholders (including USGS):
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By September 30, 2012
By September 30, 2013
Oct 1, 2013 - Sept 30, 2014: Sensitivity
analysis, review, collect comments, adopt
for various applications (including National
Seismic Hazard Maps)
Workshops…
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We will have numerous workshops
As part of SSHAC process; and also to:
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To collect feedback and comments from the
community
To give information about the NGA-East
project
Next SSHAC workshop: Critical issues and
data needs. On November 15-18, 2010 at
UC Berkeley…please register at PEER web
site (free of charge) and attend
NGA-West 2 Project
NGA-West 2
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Follow-up of NGA-West 1 to address the
issues and topics that we did not have
opportunity to address in the previous
phase
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And, update the NGA-West 1 models
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Funding agencies:
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California Earthquake Authority (CEA)
Caltrans
PG&E
USGS
FEMA
NGA-West 2: Topics
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Finalize directivity model(s) for NGAWest
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Directionality issues for NGA-West
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GMPEs for vertical ground motion
Recall, NGA-West 1 models were for
horizontal motion
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Verification of NGA models for small
magnitude data
To reduce the conservatism of NGA-West 1
GMPEs for small magnitude data
NGA-West 2: Topics
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Verification of NGA models for recent
moderate and large magnitude events
worldwide
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Compilation of the NGA-West 1 database
was stopped in mid-2003
The new expanded database is larger by
70% (3,500 versus 6,000 recordings)
2004 Parkfied EQ, Wenchuan EQ (M 7.9),
Italian EQs, Japanese Eqs, Baja EQ, …
The most comprehensive empirical
database, including metadata, ever
compiled for shallow crustal EQs in active
tectonic regions
NGA-West 2: Topics
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Scaling NGA models for damping other
than 5%
Development of epistemic and aleatory
uncertainty models (joint with NGAEast)
Further development of site response in
NGA
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Current NGA-West 1 site amplification
factors are inconsistent with NEHRP factors
Goal: To make NEHRP and NGA site amps
consistent
NGA-West 2: A Tentative Topic
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(Tentative—now becoming serious)
Development of GMPEs for maximum
direction horizontal ground motion
NGA-West 2 Project Duration
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NGA-West 2 project will be completed by
August 31, 2012
Global GMPEs for
Global Earthquake Model (GEM)
Project
 Goal: To select a suite of GMPEs for
global and regional levels, by using a
collaborative approach
 Duration: 24 months
 Team: 27 international experts from
around the world
Tasks
 Task 1: Definition of a consistent strategy of
modelling ground motion
 consistency in model parameters
 consistency in site parameters
 Task 2: Compilation and critical review of
GMPEs for:
 Shallow crustal earthquakes in active tectonic
regions
 Stable continental regions
 Subduction regions
 Volcanic earthquakes
Tasks
 Task 3: Selection a set of Global GMPEs
 Task 4: Inclusion of near-fault effects
 Task 5: Database of Recorded Waveform
 Task 6: Specifications for compilation of a
global database of Soil Classification
Summary
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Three major ground motion programs
are currently coordinated by PEER:
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NGA-East
NGA-West 2
GEM
Each program has several supporting
technical working groups
Summary
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Many senior researchers, post-docs,
graduate students, practitioners,
end users, regulators, … are involved
Coordination of such large programs
would have been extremely
challenging if wanted to carry it out
outside of a national research center
THANK YOU!