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

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

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

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

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,…

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

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

GMPE Development

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

Working Groups

NGA-East is a SSHAC Level 3 Project

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 Draft GMPEs to be ready for internal

(SSHAC) review: By September 30, 2012

GMPEs to be ready for review by various stakeholders (including USGS): 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… We will have numerous workshops As part of SSHAC process; and also to:

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

Follow-up of NGA-West 1 to address the issues and topics that we did not have opportunity to address in the previous phase

And, update the NGA-West 1 models

Funding agencies: California Earthquake Authority (CEA) Caltrans PG&E USGS FEMA

NGA-West 2: Topics

Finalize directivity model(s) for NGA-West

Directionality issues for NGA-West

GMPEs for vertical ground motionRecall, NGA-West 1 models were for horizontal motion

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

Verification of NGA models for recent moderate and large magnitude events worldwide 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

Scaling NGA models for damping other than 5%

Development of epistemic and aleatory uncertainty models (joint with NGA-East)

Further development of site response in NGA Current NGA-West 1 site amplification

factors are inconsistent with NEHRP factors Goal: To make NEHRP and NGA site amps

consistent

(Tentative—now becoming serious) Development of GMPEs for maximum direction horizontal ground motion

NGA-West 2: A Tentative Topic

NGA-West 2 Project Duration

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

Three major ground motion programs are currently coordinated by PEER: NGA-East NGA-West 2 GEM

Each program has several supporting technical working groups

Summary

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!