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CUREE Publication No. CS-07

Proceedings of the NSF-CUREEWorkshop on Strong-Motion

Research Needs and Opportunities

Oakland, CaliforniaOctober 19-20, 2006

Edited by

Wilfred IwanCalifornia Institute of Technology

Sponsored by

National Science Foundation

Presented by

Consortium of Universities for Research in Earthquake Engineering

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Proceedings of the NSF-CUREEWorkshop on Strong-Motion

Research Needs and Opportunities

Oakland, CaliforniaOctober 19-20, 2006

Sponsored by

National Science Foundationawarded under Grant: CMS-0403755

Consortium of Universities for Research in Earthquake Engineering1301 South 46th Street - Building 420

Richmond, CA 94804tel.: 510.665.3529 fax.: 510.665.3622 web.: www.curee.org

CUREE

CUREE Publication No. CS-07

Edited by

Wilfred IwanCalifornia Institute of Technology

ii

ISBN 1-931995-27-3

First Printing: June 2007

Printed in the United States of America

Published byConsortium of Universities for Research in Earthquake Engineering (CUREE)1301 South 46th Street - Building 420, Richmond, CA 94804-4600www.curee.org

CUREE

Table of Contents | iii

Table of Contents Page

Acknowledgements .......................................................................................................................iv Summary ........................................................................................................................................v Chapter 1 – Introduction ..............................................................................................................1

Chapter 2 – Conclusions and Recommendations .......................................................................5

Chapter 3 – Overview of Major Strong Motion Programs – Goals, Strategy, and Status...13

3.1 California Strong Motion Instrumentation Program (CSMIP)....................................13 3.2 Advanced National Seismic System (ANSS)..............................................................17 3.3 Japan ............................................................................................................................20 3.4 China............................................................................................................................24 3.5 Taiwan .........................................................................................................................26 3.6 Mexico.........................................................................................................................30 3.7 George E. Brown, Jr. - Network for Earthquake Engineering Simulation (NEES) ....33 3.8 Other US programs......................................................................................................34

Chapter 4 – Current Applications and Future Visions for Strong-Motion Research ..........37 4.1 An Academic Perspective............................................................................................37 4.2 A Practitioner’s Perspective ........................................................................................40 4.3 A Risk Perspective ......................................................................................................42

Chapter 5 – Working Group Findings ......................................................................................49

5.1 Working Group 1 – Bret Lizundia (Chair), Jacobo Bielak (Recorder) .......................49 5.2 Working Group 2 – Andrew Whittaker (Chair), Mark Sinclair (Recorder) ................52 5.3 Working Group 3 – James Beck (Chair), James Goltz (Recorder) .............................54

Chapter 6 – References ...............................................................................................................57 Appendices ...................................................................................................................................60

Appendix A - Workshop Agenda ......................................................................................60 Appendix B - Workshop Photographs...............................................................................62

iv | NSF-CUREE Workshop on Strong-Motion Research Needs and Opportunities

Acknowledgements The contributions of the following participants are gratefully acknowledged: Organizing Committee Craig Comartin, CDC Comartin C. B. Crouse, URS Corporation Gregory Fenves, University of California, Berkeley Wilfred Iwan, California Institute of Technology (Chair) Keith Porter, California Institute of Technology Robert Reitherman, CUREE Executive Director Invited Workshop Presentors John Anderson, University of Nevada, Reno C. B. Crouse, URS Corporation Greg Fenves, University of California, Berkeley Moh Huang, California Geological Survey Farzad Naeim, John A. Martin and Associates Robert Nigbor, University of California, Los Angeles Keith Porter, California Institute of Technology William Savage, U. S. Geological Survey Anthony Shakal, California Geological Survey Jamison Steidl, University of California, Santa Barbara Yi-Ben Tsai, Pacific Gas and Electric Other Invited Contributors and Participants Brad Aagaard, U.S. Geological Survey James Beck, California Institute of Technology Jacobo Bielak, Carnegie Mellon Roger Borcherdt, U. S. Geological Survey Craig Davis, Los Angeles Department of Water and Power Ahmed Elgamal, University of California, San Diego James Goltz, California Institute of Technology Thomas Heaton, California Institute of Technology Anne Kiremijian, Stanford University Bret Lizundia, Rutherford & Chekene Engineers Nico Luco, U. S. Geological Survey Sami Masri, University of Southern California Mark Sinclair, Degenkolb Engineers Andrew Whittaker, University at Buffalo, SUNY This workshop and its proceedings are dedicated to Dr. Clifford Astill of the National Science Foundation, who passed away in 2004. Dr. Astill provided the inspiration for this effort and for many years was instrumental in maintaining the high quality of the strong motion research supported by the National Science Foundation.

Summary | v

Summary

There has been great progress in strong motion instrumentation and monitoring since this

important technology was first introduced as a tool for the study of the ground motion that

resulted from earthquakes. Newer digital strong motion instruments have evolved considerably

from their old bulky analog film recorder predecessors that provided most of the historical

accelerograms that have been used in the design of structures. The new instruments have also

made data processing much easier and more reliable, and some monitoring systems are now

functioning in real-time. The number of instruments deployed for strong motion monitoring has

also grown significantly. Programs in the US have steadily expanded and programs in Asia

(particularly Japan, China, and Taiwan) have grown at near explosive rates. Those responsible

for the growth of strong motion programs world-side should be congratulated for their efforts.

Because of these efforts, the availability of strong motion data and its use to promote public

safety has improved dramatically.

However, in spite of the considerable progress that has been made in strong motion instruments

and monitoring, there is still much that remains to be accomplished in this area. This Workshop

focused on the most important research needs in strong motion studies and how these needs

might be satisfied through existing and/or new programs.

All strong motion research and programs should be goal driven with clearly articulated

objectives and strategies. The ultimate goal of these activities is societal benefit, but specific

objectives also need to be clearly stated for each sub-element of the overall effort. The more

clearly program sub-elements are related to the overarching goals of the effort, the easier it will

be to obtain public support for these efforts. While providing public benefit provides the basis

and motivation for strong motion efforts, it is also important that these efforts be cost effective in

achieving this overarching goal. This requires careful planning and monitoring of research

activities and programs.

There will always be a need for additional strong earthquake ground motion data. The present

database is not complete, being biased toward moderate earthquakes at fairly large distances

from the fault rupture. Based on the finding of this Workshop, greater emphasis should be

vi | NSF-CUREE Workshop on Strong-Motion Research Needs and Opportunities

placed on the measurement of ground motions from large earthquakes near their source. Meeting

this need presents technical as well as administrative challenges. The latest earth science studies

must be used to identify sites for instrument deployment, and there must be a commitment to

monitoring these sites for possible long periods of time before data is actually obtained.

It is the consensus opinion of the Workshop participants that currently the greatest strong motion

need is for more and better instrumentation of structural systems, primarily buildings. Although

there are many instrumented buildings in the US, only a few have sufficient sensors to enable a

comprehensive analysis of building performance into the damage state. Furthermore, in most

cases, the sensors are standard strong motion accelerometers that are fairly expensive and require

significant processing to obtain structural displacements. The situation is not much better in

other countries where proprietary restrictions on data often trump public interest.

In order to adequately instrument structural systems, there is not only a need for a greatly

increased number of channels of data, but also for improved recorder and sensor technology.

Improved sensor technology could greatly facilitate the intensive instrumentation of structural

systems. There is an urgent need for instruments that are cheaper, easier to deploy, and easier to

maintain. Also, there is a need for instruments that directly measure displacements (drifts and

rotations), thus avoiding the need for double integration of accelerometer data. Data availability

and management are crucial to the success of any strong motion program. Open and easy access

to data is vital to meeting public safety goals. A wide range of users can benefit from the results

of strong motion research and programs, but only if the data, both raw and processed, are readily

available. Furthermore, the selection of structures should be made with appropriate

consideration of the type of structural system, the type of ground motion that may be expected

during the life of the instrumentation system, and the level of structural response (degree of

damage) that is anticipated.

Finally, it is important that strong motion research and programs involve a multi-disciplinary

coalition in developing objectives and outcomes. This coalition must include the key potential

users of strong motion data as well as those who obtain and manage the data. There is a broad

range of applications of strong motion data and it is essential to have the broadest possible

Summary | vii

involvement of all stakeholders in this data. At present, most decisions are made by the

technical, scientific, or administrative communities. The utilization of strong motion research

and data will increase when the broader emergency response and management, community

planning, and social science communities are involved in key decisions.

Whether for ground motion or structural monitoring, there should be a strong and well

articulated connection between the technical aspects of the deployment and public benefit. There

are many potential public benefits of strong motion programs, but sometimes these benefits are

not well connected to the technical objectives of the program. Even when there is a fairly clear

connection between the technical and public interest objectives, this connection is sometimes not

well presented.

It is unlikely that existing US strong motion programs will be able to fully meet the needs

identified by the participants of this Workshop. At present, the existing programs either do not

have sufficient resources or the appropriate mission. For that reason, a new program structure

may be required to meet these needs. The new program structure would need to be established at

a high level in order to be viable and sustainable. A new program within NEHRP has been

proposed with possible direct funding within that program. This may be the only way to achieve

the vision of the Workshop participants. These proceedings present several options for

implementation of the recommendations made.

This Executive Summary is intended to summarize the major conclusions and recommendations

of the Workshop in a very concise form. The author believes that this summary accurately

reflects the majority (consensus) opinion of the Workshop participants, but ultimately the

summary reflects the understanding of its author.

W. D. Iwan, Editor

viii | NSF-CUREE Workshop on Strong-Motion Research Needs and Opportunities

Introduction | 1

Chapter 1 Introduction

Introduction

Earthquakes pose a serious hazard in many parts of the United States, and the costs of a future

major earthquake in a populated region could be enormous in terms of lives lost, physical

damage, and overall societal impact. The purpose of strong motion research and programs is to

reduce the impacts of earthquakes through a better and more timely understanding of the nature

of earthquake ground motion and the response of the built environment to this motion. The

potential benefits of strong motion research and programs include reduced casualties and

economic losses from earthquake disasters through improved building codes and standards,

improved emergency response and disaster management, more rapid restoration of business and

government activity following a disaster, better and faster repair of damaged structures, and

faster incorporation of lessons learned into future mitigation strategies.

In 1978, NSF sponsored the International Workshop on Strong Motion Earthquake Instrument

Arrays (Iwan, 1978). This workshop, usually referred to as the Hawaii Workshop, represented a

watershed in the deployment of instruments to measure strong earthquake ground motions. The

recommendations of this workshop have had far reaching consequences, guiding the design and

installation of strong motion arrays throughout the world. The workshop participants identified

28 favorable world-wide locations for the deployment of strong motion arrays and classified six

of these as high priority locations. The first array was deployed shortly after the workshop in

Taiwan, one of the six high priority sites. Subsequently, strong motion arrays were deployed in

California, Mexico and Japan, all identified as high priority sites, and in china and other

countries. Over the years of their operation, the arrays that were installed as either a direct or

indirect consequence of this workshop have provided important, useful data that have greatly

improved our understanding of strong earthquake ground motion and the effects of this motion

on the built environment.

As a follow-up to the Hawaii Workshop, in 1981 NSF sponsored the US National Workshop on

Strong-Motion Earthquake Instrumentation (Iwan, 1981). The purpose of this workshop was to

2 | NSF-CUREE Workshop on Strong-Motion Research Needs and Opportunities

review the status of strong motion instrumentation programs within the United States and to

develop a strategy to meet future national strong motion instrumentation needs. For many years,

the proceedings of this workshop have served as a reference for the deployment of arrays and

other strong motion earthquake instrument installations. The proceedings set forth specific

recommendations for the deployment of ground motion stations as well as structural response

applications. It also introduced the concept of mobile arrays. The proceedings also contained an

in depth analysis of issues related to the processing, cataloging, archiving, and dissemination of

strong motion data as well as consideration of program funding and management.

These and other workshops and reports sponsored by NSF and other agencies have been useful

in identifying needs and opportunities for strong motion earthquake instrumentation and in

proposing strategies to meet these needs. However, recent developments in instrument

technology, new applications opportunities, and changing user needs indicate that it is time to

take a fresh look at strong motion earthquake instrument deployment. Important new concerns

have arisen regarding the nature of ground shaking relating to such issues as near-field effects,

soil-structure interaction, and basin effects. Also, there is a realization that there is insufficient

strong motion data to be able to fully understand the response of structural systems all the way

up to failure. Without such data, it will not be possible to make significant strides in addressing

the ultimate problem of structural collapse, which is arguably the primary cause of life loss in

disasters. At the same time, new instruments are providing additional options and opportunities

for the measurement and storage of strong motion data. The recently established Advanced

National Seismic System (ANSS) and the Network for Earthquake Engineering Simulation

(NEES) Program are both being affected by these new developments in strong motion

instrumentation.

For the reasons stated above, it was believed that this an ideal time to reassess the status of

strong motion instrumentation in the United States and to develop new strategies to insure

accelerated progress in this field. The individuals who initially envisioned this workshop

thought it especially important at this juncture that an assessment be made of the future role of

the NSF earthquake engineering research programs in support of other strong motion

instrumentation activity.

Introduction | 3

The need for this workshop was initially recognized by the late Dr. Clifford Astill of the NSF

who provided the inspiration for this effort and for many years was instrumental in maintaining

the high quality of the strong motion research supported by the NSF, and to whom these

proceedings are dedicated. Wilfred Iwan was the Principal Investigator for the workshop

project, and oversight for the planning and conduct of the workshop was provided by a Steering

Committee consisting of: Craig Comartin, Charles B. Crouse, Gregory Fenves, Keith Porter

(Secretary), Robert Reitherman, and Wilfred Iwan (Chair). There were several delays in the

holding of the workshop due to illness of the Principal Investigator, but the workshop was held

successfully in October of 2006.

As they have evolved during the planning phase, the objectives of this NSF-CUREE Strong

Motion Workshop were to:

• Summarize the goals, objectives and accomplishments of significant current national and

international strong-motion programs,

• Identify high priority needs and opportunities for US strong-motion research,

• Develop the rationale for this priority research, and

• Draft cost effective strategies by which this research can be successfully accomplished.

The workshop was organized into three distinct elements:

• A review of the goals, objectives, strategies, accomplishments, and status of major US

and foreign strong-motion programs,

• Stimulation of thinking regarding important current applications and future opportunities

for strong-motion research , and

• Development of recommendations for future strong-motion research.

The first element consisted of a series of overview presentations of major strong motion

programs in the US and other countries. These presentations were given by individuals having a

special identification with and knowledge of these major programs, and provided the basis for

the subsequent discussions of future research plans. The presentations were made in the form of


Power Point presentations, which are contained in their entirety in the CD attached to these

proceedings.

The second element consisted of a series of “vision” presentations made by specially selected

individuals representing three different aspects of the strong motion data user community. These

included the academic community, the practicing structural engineering community, and the risk

analysis community. These Power Point presentations are also contained in their entirety in the

CD attached to these proceedings.

The third element was addressed through three different Working Groups. Each Working Group

was intentionally given the same assignment so that there would be greater breadth of thinking

about the common issues. The Working Groups were instructed not to prepare a laundry list of

research topics, but to instead identify a few high priority research needs and/or opportunities

along with clear goals and objectives for this research. They were also instructed to develop

statements of justification for these high priority research topics, and identify basic strategies

that could be employed to accomplish the identified objectives.

The three Working Groups presented their findings to the workshop participants and there was a

general plenary discussion of all of these findings. The findings and recommendations of the

individual Working Groups are given in outline form in these proceedings. The synthesized

summary conclusions and recommendations of the workshop are also presented.

Conclusions and Recommendations | 5

Chapter 2 Conclusions and Recommendations

In working group and plenary discussions, the workshop participants reached a consensus on a

set of conclusions and recommendations for future strong motion efforts in the United States that

are summarized below.

1. The importance of well-defined goals and objectives Without the implementation of effective mitigation strategies, the costs of a future major

earthquake in a populated region of the US could be enormous in terms of lives lost, physical

damage, and societal impact. But development of effective mitigation strategies depends on

having knowledge of the nature of the ground shaking associated with the earthquake event and

the associated response of the built environment to this shaking. Strong motion monitoring

research and programs provide this knowledge.

The ultimate goal of all strong motion activity should be to provide benefit to society, including

both the public and private sectors, and it is the responsibility of those managing strong motion

research and programs to provide the rationale for how their programs will address this ultimate

goal and to establish specific achievable objectives that support this ultimate goal.

Possible public benefits of strong motion efforts include reduced casualties and economic losses

from earthquake disasters through improved building codes and community planning, improved

emergency response and disaster management, more rapid restoration of business and

government activity following a disaster, better and faster repair of damaged structures, and

faster incorporation of lessons learned into future mitigation strategies.

2. Societal benefit versus cost While it is important that strong motion programs have large overarching goals and specific

objectives, they should also optimize the trade-off between benefits and costs. This requires a

careful examination of the strengths and weaknesses of current strong motion efforts, and how

these affect our ability to achieve the ultimate goal of societal benefit. The workshop

participants looked specifically at this issue and the recommendations below address the need for


additional resources for strong motion activities as well as possible reallocation of resources

within strong motion activities.

3. Strong motion research and programmatic need for more cost effective support of the societal benefit goal In plenary discussion, the Workshop participants agreed that there was a need to refocus strong

motion research and program activities in order that they become more cost effective in

supporting the overarching goal of societal benefit. There was general consensus regarding the

items indicated below:

• Improve how strong motion data is used to reduce the impact of earthquakes on the

social and economic infrastructure. Strong motion data is used by a broad spectrum of scientists and engineers and its use has

resulted in very significant improvements in seismic safety through better land use

planning, more effective codes and standards of design, and better construction practice.

However, there are many more potential applications of strong motion data that have not

yet been fully implemented. The use of strong motion data for advanced risk assessment,

and the use of real-time strong motion data for emergency response and recovery

decision-making warrant further research and application. These, and any other new

applications of strong motion data, should be driven by the societal benefit goal that is set

forth at the beginning of these recommendations.

• Deploy more strong motion instruments in buildings and other structures. The California Integrated Seismic Network (CISN) has an integrated program for ground

motion monitoring, but not for structural monitoring. The California Strong-Motion

Instrumentation Program is essentially the only US-based program that has a significant

structural element, but this program cannot meet the need on its own. So far, the

Advanced National Seismic System (ANSS) has not achieved its objectives for structural

instrumentation, and other countries cannot be relied upon for needed structural

performance data as their structural instrumentation programs are generally highly

proprietary and their structures are built according to different codes and standards than

in the US. There is an urgent need to expand the instrumentation of structures within the


US in order to have an adequate database for understanding the performance of structures

during strong earthquake ground motions and to improve codes and standards to make

these structures safer and more cost effective. In order to meet the needs for recording structural strong motion, it may be necessary to

create a large national program focused specifically on this need. The current level of

structural instrumentation is generally inadequate to obtain the required detail of the

structural response to really understand the performance of a structure. Many structures

with hundreds of sensors each are needed. It is doubtful that any existing strong motion

program will be capable of addressing this need. Thus, a new program will likely be

needed.

An important element of any expanded structure instrumentation program would be to

have this program integrated to the same extent that current ground motion programs are

integrated between operating agencies through such means as the Virtual Data Center of

the Consortium of Organizations for Strong Motion Observation Systems (COSMOS).

Such integration provides the user much easier access to the data and thereby promotes

its use.

• Deploy more ground motion instruments, especially near major active faults. There are a great many strong ground motion stations in the US and throughout the world

and these have yielded considerable useful data on the nature of strong ground shaking

during moderate to strong earthquakes and at moderate distances from the causative fault.

The data are generally readily available through the Internet, and have been used by

many countries to update building codes and standards so that newer structures generally

have a higher margin of safety than older ones. It may be argued that there is currently sufficient data for moderate earthquakes at

moderate distances from the fault. But it is generally agreed that there is insufficient data

for very large earthquakes and for sites near the fault or sites affected by important basin

effects and other geological and geotechnical factors. Therefore, there is a need for


additional free-field ground motion sites, especially for those sites with very high damage

potential.

• Develop less expensive and easier to deploy integrated sensors to measure ground and structural acceleration. Current strong motion instruments are primarily accelerographs. There have been many

improvements to instruments over the years, but they are basically similar to their early

design, consisting of a force-balance accelerometer, a data recorder, and possibly some

means for remote data access or real-time data transmission. The instruments are

somewhat bulky, and most require significant wiring and stable high capacity power

supply. Considerable research has been devoted to the development of a new generation of small,

low cost, low power, wireless acceleration sensors, but these have not yet been deployed

on any large scale due to concerns about accuracy and reliability. It is important that

such research continue and that those involved in developing new accelerographs make it

a priority to demonstrate their accuracy and long-term reliability in real-life applications.

• Develop economical and easily deployed displacement sensors for both structural and ground measurement.

Current strong ground motion and structural instrumentation is almost exclusively

acceleration-based. Over the years, improvements have been made in the recording

(especially the transition from analog to digital recording) of data and the processing of

this data so that acceleration can be used to generate reasonably accurate velocity and

displacement time histories. However, the direct measurement of displacement at

frequencies up to about 20 Hz would be highly desirable. In building structures, interstory drift is an important measure of structural demand. It

would be extremely valuable if there were an inexpensive and unobtrusive way to

measure and record (or transmit real-time) interstory drift data from earthquake response.

This allows the data to be more easily and directly related to structural performance

evaluation and prediction.


• Optimize how strong motion instruments are deployed for maximum cost effectiveness.

Although there is a clear and justifiable need for expanded strong motion efforts, it is

unlikely that there will be any significant increase in funding for strong motion programs

and research in the near future. Therefore, it is important to find ways to optimize how

instruments are deployed so as to maximize the benefits derived. Given limited

resources, both now and in the future, this will require the development of a strategy and

rationale for deciding where and instruments should be installed and how many

instruments should be dedicated to different objectives. This will not be an easy task as

there are many competing priorities that must be balanced. But this is vital to achieving

the overarching goal of strong motion studies and necessary to demonstrate that limited

resources are being used appropriately. Developing an optimal deployment strategy is an

important first step in obtaining additional resources for strong motion efforts.

• Establish greater multidisciplinary coordination in the installation and use of strong motion instrumentation.

The measurement of strong ground motion is important to a number of different

disciplines who rely upon this data for advances in understanding earthquakes. This

includes geologists, seismologists, geotechnical engineers, structural engineers, and

others. Therefore, it is important that any expanded strong motion efforts be well

integrated across these disciplines. There is a tendency for strong motion programs to be

dominated by the interests of the agency responsible for their operation even though the

use of the data is much broader. This should be recognized and steps taken to provide

effective integration of all strong motion programs.


4. Possible strategies to meet the need for expanded strong motion efforts In plenary session, the Workshop participants discussed a number of possible strategies to meet

the need for expanded strong motion efforts in the US. Although there was no general consensus

on which of these strategies would be most effective, it was agreed that one or more of the

following strategies should be pursued.

• Work through existing strong motion programs.

Both the California Strong Motion Instrumentation Program and the ANSS program of

the USGS offer opportunities for achieving some of the needs pointed out in this

workshop. These opportunities should be energetically pursued by the strong motion

community. However, each of these programs has its own objectives and limited

resources, which makes it difficult for them to adopt all of the recommendations set forth

by this workshop. NEES presents an opportunity for implementation of some of the

research needs set forth by the workshop participants. But the resources of that program

are also limited and the primary focus is on large-scale laboratory research.

• Work through new channels not currently involved in strong motion activity. Another option to achieve the needs pointed out in this workshop would be to work

through new channels. One possible new channel would be the insurance and liability

sector. This sector has potentially much to gain from expanded strong motion efforts.

However, the case for their participation has not yet been effectively made. This is

something that needs to be looked into further and warrants the attention of the entire

strong motion community.

• Create a large umbrella strong motion initative

One of the Working Groups came up with the idea of developing a large initiative in

strong motion studies. This would essentially create a “living laboratory” for ground

motion and structural response studies. Such a laboratory would be different from the

NEES laboratories, but might share some components and objectives. Such an initiative

would obviously require a concerted effort by the entire strong motion community.


5. Next steps in developing an action plan There was considerable discussion of what the next steps might be to address the needs and

strategies identified by the workshop participants. Although a specific action plan was not

developed by the participants, it was agreed that the following elements are important in any

such plan.

• Recommend to USGS that they take greater responsibility for the needs identified by the workshop participants.

The USGS could implement some of the recommendations of this workshop through the

ANSS program. The workshop participants felt that the USGS should be encouraged to

take this step. However, it was recognized that there were sufficient differences between

the mission of ANSS and the goals and objectives presented by the workshop participants

that it would not be possible for ANSS to fully meet the needs identified. Therefore, the

participants generally looked to other implementation approaches.

• Form a Joint Commission on Strong Motion Instrumentation.

Any effort to expand strong motion studies in the areas considered by this workshop must

begin with a broad coalition of the willing. There is no way to force individuals or

organizations to pursue the agenda outlined herein. COSMOS may be able to provide

initial assistance in developing a broader coalition. However, this organization has a

much narrower focus and is closely tied to existing strong motion programs, making it

difficult for it to take a leadership role in implementing a much broader future vision.

In order to obtain a broad “grass-roots” coalition, it may be necessary to form a new

entity such as a Joint Commission on Strong Motion Instrumentation (JCSMI). This

entity should represent all of the stakeholders in strong motion instrumentation studies

including the earth science, engineering, risk, planning, emergency response, and social

science communities.

A great deal of effort and commitment would be needed to form a JCSMI. The first step

in the formation process might be to convene a planning workshop within the coalition of

the willing. Sponsorship for this planning event would need to be found.


• Directly approach Congress through NEHRP with the need for a new program focused on strong motion studies.

It was generally agreed that there is a significant gap in the present NEHRP program as

regards strong motion studies of the type identified in this workshop. Therefore, after

formation of a JCSMI, or some other coalition of the willing, it may be appropriate to

make a direct approach to Congress through the NEHRP for a greatly expanded strong

motion program. Since structural instrumentation is a very significant part of the

expanded strong motion effort envisioned by the workshop participants, it was believed

that NIST, who has overall responsibility for the NEHRP, might be a good choice for the

agency with responsibility for this new program. It was agreed that NIST should be

briefed on the results of this workshop and invited to participate in the future planning

process for an expanded strong motion effort. As regards the structure of a possible new federal strong motion program, it was

generally agreed that the California Strong Motion Instrumentation Program provides a

good model. This program has many of the characteristics desired by the workshop

participants including: a public benefit focus, influential stakeholder advisory

committees, rapidly available data, and a significant data utilization program.

Overview of Major Strong Motion Programs – Goals, Strategy, and Status | 13

Chapter 3 Overview of Major Strong Motion Programs –

Goals, Strategy, and Status In order to provide a sound basis for the discussion of future strong motion needs, invited

presentations were given by individuals with special knowledge regarding existing strong motion

programs in the US, China, Mexico, Japan, Taiwan, and other countries. Abstracts of these

presentations are provided below. Complete PowerPoint presentations are contained on the CD-

ROM attached to these proceedings.

Great effort went into the preparation of these presentations, and collectively they provide a

valuable reference indicating the current level of strong motion activity throughout the world. As

such, these reports provide the basis for many of the conclusions and recommendations

presented in these proceedings.

3.1. California Strong Motion Instrumentation Program –

Goals, Strategy and Status Anthony Shakal and Moh Huang (California Geological Survey)

The California Strong Motion Instrumentation Program (CSMIP) was established after the

damaging 1971 San Fernando to increase strong-motion data for earthquake engineering

applications. A statewide network of strong motion stations was initiated to obtain data on what

ground motion level structures needed to be designed, for and data on how structures responded

to the input strong shaking. After the 1994 Northridge earthquake, CSMIP program activities

were expanded to include providing post-earthquake data to guide emergency response. An

external committee of specialists from industry, government and universities, the Strong Motion

Instrumentation Advisory Committee, is an important element of program progress. CSMIP is

funded primarily from building-permit fees, with additional funding from Caltrans for bridge

instrumentation, from OSHPD for hospital instrumentation, and OES for emergency response.

The CSMIP network now has about 1060 stations, including 760 free field sites, 180

instrumented buildings, 65 bridges, 25 dams, and 22 subsurface geotechnical arrays.


Figure 3.1.1


A major CSMIP focus is the instrumentation of buildings to improve (and verify) seismic

designs and practices through measurement of motion during strong earthquake shaking.

Selected structures are instrumented to measure input motion and key aspects of the structural

response. Building instrumentation objectives and the selection of buildings follows a long-term

plan and criteria established in cooperation with the SMIAC Buildings Subcommittee. The long-

term goal includes a total of 400 buildings, which are broken down into 30 groups, based on

construction type, lateral force-resisting system, and building height. The groups are further

subdivided into a total of 133 representative types according to distribution of force-resisting

elements and year of construction. Three candidates of each type, located in different seismic

regimes, are targeted to increase the likelihood of early recording. An objective is that a record

of significant structural response be obtained as soon as possible in each representative building

type to assess performance and verify and improve design. Instrumentation priorities are based

on the prevalence and estimated vulnerability of the structural system and the information

needed for the specific type.

In a typical building instrumentation plan, sensors are located at key structural members

throughout building. The locations are based on the lateral force-resisting system so that

important modes of vibration will be recorded. Overall goals include the measurement of the

input ground motion, the building base motion, lateral floor motions, torsional floor motions,

floor/wall diaphragm motions, and shear-wall rocking motions. Recorded data have provided

valuable information on the seismic response of existing buildings as well as information needed

for improving design codes and procedures for new structures. Near-real-time recovery and

processing of data is becoming increasingly valuable for post-earthquake evaluation of structural

performance and structural integrity assessment.

In addition to free field and structural instrumentation, subsurface geotechnical arrays are an

important instrumentation component. CSMIP now has 22 geotechnical arrays instrumented,

each with 6 to 21 accelerometers. Many of the arrays were installed in partnership with Caltrans.

The most extensive array is at Treasure Island, near San Francisco. The deepest array is at La

Cienega, in Los Angeles, with a depth of 250 m; most arrays are shallower, many 50 m or less.


Array geologic site conditions range from deep, soft soil sites to stiff soils. Data recorded thus

far are mostly of low amplitude.

CSMIP has an active data utilization and outreach component. Some data utilization projects

include ATC-54, Guidelines for Utilizing Strong-Motion Data and ShakeMaps in Post-

Earthquake Response, and the CSMIP-3DV Building Response Analysis and 3D Visualization

System. Annual SMIP Seminars are held each year, to review progress on data utilization

projects, and the proceedings are available at www.consrv.ca.gov/cgs/smip.

Since the 1994 Northridge earthquake, CSMIP has partnered with other seismic networks

operating in California, including Caltech, UC Berkeley and the USGS, to form the California

Integrated Seismic Network (CISN) for the purpose of improving seismic recording for post-

earthquake response. The partnership was made possible by advances in seismic

instrumentation, since wide dynamic range recorders allow recording of both weak and strong

motion. Also, communication technology has made it possible to recover data and provide

processed information on shaking within minutes of an earthquake. ShakeMap is an important

product developed during this integration.

Another important partnership being established is the National Center for Engineering Strong

Motion Data (NCESMD), a cooperative effort of CSMIP and the USGS National Strong Motion

Instrumentation Project and Advanced National Seismic System (ANSS) to collect strong-

motion data for engineering use into a single, unified National Center. The NCESMD will

integrate procedures in Sacramento and Menlo Park for processing, archiving and accessing data.

It will increase efficiency in the use of state and federal funds while improving the quality and

ease of access to the nation’s strong-motion data for engineering applications.


3.2. Advanced National Seismic System (ANSS) – Goals, Strategy, and Status William U. Savage (US Geological Survey)

The Advanced National Seismic System (ANSS) is a major initiative of the Earthquake Hazards

Program of the U. S. Geological Survey to modernize and expand earthquake monitoring in the

U. S. in order to address current and ongoing needs of the engineering, emergency response, and

Earth sciences communities, with the goal of reducing the loss of life and property in

earthquakes, tsunamis, and volcanic eruptions. The plan for ANSS was developed in the late

1990s as a partnership between the USGS and more than a dozen regional seismic monitoring

networks in the nation (USGS Circular 1188). Of the 7,100 new or upgraded seismic stations

planned, 3,000 are strong-motion ground response stations targeting 26 at-risk urban areas and

3,000 instruments (9,000 data channels) are designated for measuring strong shaking responses

of buildings, bridges, and other structures. Unfortunately, the planned 5-year installation of

ANSS with a total budget of $172M ($35M per year) has been only partially funded; since 2000,

annual funding has grown to just over $8M. Nonetheless, progress has been made on many

aspects of the ANSS plan:

• About 550 strong-motion ground-response stations have been installed in partnership

with regional seismic networks to build ShakeMap capabilities and address engineering

needs in the San Francisco Bay area, Seattle, Anchorage, Salt Lake City, Reno, and the

New Madrid region.

• Four structures have been instrumented under ANSS, with another 8 in process in 2006-

2007, thus representing an increasing emphasis on the structural response monitoring

component of ANSS.

• The National Earthquake Information Center in Golden, CO, has been upgraded with

modernized software and 24x7 operations to speed national and global earthquake

notifications.

• Regional seismic networks have integrated real-time strong-motion accelerographs with

traditional seismological instruments for more comprehensive monitoring of active faults

and source zones.


• To better serve the needs of the engineering users of strong-motion data, USGS and the

California Geological Survey have established the US National Center for Engineering

Strong-Motion Data, jointly operated by the California Strong-Motion Instrumentation

Program and the National Strong-Motion Project. This National Center expands the

functionality of the CISN Engineering Data Center to provide corrected and processed

time histories, response spectra, and metadata for the ground-response and structural-

response stations operated by the many partners of ANSS across the nation. Operation of

the COSMOS Virtual Data Center, providing searchable access to international data, will

be maintained as part of the National Center.

• Thirty-nine new or upgraded seismic stations have been added to the ANSS National

Backbone through the National Science Foundation EarthScope Project.


Figure 3.2.1


3.3. Japanese Strong Motion Data

C.B. Crouse (URS Corporation)

The Japanese strong motion program can be conveniently split into two 25-year periods

beginning with the early history from 1955 to 1980. During this period, the SMAC

accelerograph was by far the most prevalent instrument deployed to measure strong ground

motion in Japan. Most of the accelerograms recorded during this period were from networks

operated by the Port and Harbor Research Institute (PHRI) and the Public Works Research

Institute (PWRI).

A total of 177 digitized components of the more significant accelerograms recorded between

1955 and 1980 were collected from the PHRI, PWRI, and a few other Japanese sources (Mori

and Crouse, 1981). These records were then corrected for instrument response and baseline

drift. The uncorrected and corrected accelereogram data can be obtained from the National

Geophysical Data Center of the National Oceanic and Atmospheric Administration through its

website, www.ngdc.noaa.gov. Details of the collection and processing of these records can be

found in the Mori and Crouse (1981) report, which is also on this website. This report also

presents plots of the acceleration, velocity and displacement traces for each record.

The design of the SMAC accelerograph was relatively simple and it recorded many significant

strong motion accelerograms including the first global recording of a site that liquefied (1964

Nigata earthquake of moment magnitude M 7.5), and the first multiple recordings of a great M ≥

8 earthquake (1968 Tokachi-oki earthquake of M 8.2). However, the SMAC accelerograph was

quite massive (100 km), and it severely filtered motions with frequencies greater than a few

hertz.

During the last 25 years, the SMAC accelerographs have gradually diminished and compact,

digital, broad banded, strong motion accelerographs have emerged in Japan. In 1996, the

National Research Institute for Earth Science an Disaster Prevention (NIED) began construction

of a dense nationwide strong motion network of about 1,000 surface level observation stations

with a spacing of about 25km. This network is called K-NET. Each station has a digital strong

motion instrument, and data are fed to a control center at NIED in Tsukuba through an ISDN


line. The peak ground acceleration is quickly distributed by FAX and email following an

earthquake, and accelerograms are posted on the web within a few days (Kashima, 2000).

NIED has also deployed a digital network of about 500 surface and down-hole bedrock strong

motion stations throughout Japan. This network is called KiK-NET. Figure 3.3.1 shows the

distribution of the K-NET and KiK-NET sites throughout Japan.

Figure 3.3.1 Distribution of K-NET stations (indicated with blue dots) and KiK-NET stations (indicated with green dots) throughout Japan (Kashima, 2000)


The strong motion data from both the K-NET and KiK-NET networks are available through the

COSMOS Virtual Data Center (www.cosmos-eq.org). Among the many K-NET and Kik-NET

records available on this website, one hundred are from the 2003 Tokachi-oki earthquake of M 8.3.

The building Research Institute (BRI) of Japan also operates a nation wide strong motion

network of approximately 50 digital instruments in major cities in Japan. These instruments are

primarily deployed in buildings with sensors located on the top floor and basement of the

building and possibly in the free-field. It was this network that recorded the noteworthy Niigata

earthquake records referred to above. Stations in this network are connected to the BRI by

telephone. Dense strong motion arrays are also deployed in some populated areas of Japan,

notably in the Sendai and Tokyo metropolitan regions. The BRI station map is shown in

Figure 3.3.2

Figure 3.3.2 BRI strong motion site map (Kashima, 2000)


Various corporations and agencies in Japan deploy strong motion arrays in buildings, but the

data are often proprietary. One exception is the Urban Disaster Prevention Research Center

Annex building of the BRI in Tsukuba. This eight-story building and its surroundings are

extensively monitored for the purpose of building and soil-structure interaction studies.

Figure 3.3.3


3.4. Strong Motion Project in China – Goals, Strategy and Status Xiaojun Li Institute of Engineering Mechanics - China Earthquake Administration Moh Huang (presenter) Strong Motion Instrumentation Program - California Geological Survey

The China Earthquake Administration (CEA) began the tenth five-year program to improve

earthquake monitoring and reduce earthquake disaster in major cities. The program includes six

projects: 1) seismic network, 2) seismic precursor network, 3) strong motion network, 4) active

fault investigation in main cities, 5) earthquake emergency and rescue system, and 6) seismic

information/data system. The total investment on the five-year program is about $300 million.

The strong motion project includes 1160 permanent ground stations distributed in high seismic

areas, 280 stations for rapid intensity reporting in five urban areas, 12 special arrays for near

fault ground motion, site effect, topography effect and structural response, and 200 mobile

stations. The total cost on the strong motion project is $40 million. The installations of these

strong-motion stations are scheduled for completion by the end of 2006. Figure 3.4.1 shows the

distribution of permanent strong-motion stations in China.


Figure 3.4.1


3.5. Strong Motion Instrumentation in Taiwan Yi-Ben Tsai (Pacific Gas and Electric)

Taiwan is an active earthquake country with high population density in its western coastal plains.

Several earthquakes in the past had inflicted disastrous loss of lives and property. Recognizing

the importance of instrumental strong motion records for mitigating the damaging effects of

earthquakes, the Central Weather Bureau (CWB) undertook a multi-year large-scale strong

motion instrumentation program since 1991. The program includes two main components, i.e.,

the free-field ground motion networks and structural arrays.

Figure 3.5.1 shows on its left side the distribution of about 700 stand-alone free-field stations in

major urban areas, and on its right side the distribution of about 80 real-time free-field stations

for rapid public reporting of the location, magnitude, and intensity of potentially damaging

earthquakes.

Figure 3.5.2 shows on its left side the locations of about 60 structural arrays in buildings and

bridges, and on its right side the train stations and electric power substations of the Taiwan

Railway Systems that are instrumented with strong motion instruments for emergency safety

operations.

For specialized research needs the Institute of Earth Sciences (IES) has installed about 30 free-

field stations in the Central Mountains, as shown on the left side of Figure 3.5.3, and about 10

down-hole arrays in Taipei Basin, as shown on the right side of Figure 3.5.3. In addition, many

dams and nuclear power plants are also instrumented with strong motion instruments by their

operators. All these modern, digital accelerographs have recorded valuable strong motion data,

including notably the 1999 M7.6 Chi-Chi earthquake in central Taiwan.


Figure 3.5.1


Figure 3.5.2


Figure 3.5.3


3.6. Strong Motion Program In Mexico: Importance To U.S. Needs In Strong Motion Studies

John G. Anderson (University of Nevada, Reno)

Worldwide, there are on average 17 earthquakes per year with magnitude M≥7, and one per year

with M≥8. Of the events with M≥7, most occur offshore in subduction zones, or at great focal

depths. Earthquakes with M≥7 in continental settings, or M≥8 in subduction zones – the type

that cause the greatest damage and loss of life – occur only about once or twice per year.

Therefore, as a general principle, if we are serious about understanding the nature of strong

earthquakes, it is essential to promote and to join a global effort to monitor strong motions

anyplace where the earthquakes occur. It would not be defensible to presume that regional

differences in earthquake ground motions are so great as to negate the value of combining the

global data set. Every time an important earthquake goes unrecorded, as several have so far in

this young century, the solution to the major unanswered questions on the nature of strong

motions is delayed by another year.

Thus the original motivation for US participation in monitoring earthquakes in Mexico remains

as strong as it was in 1980, when the Guerrero accelerograph network was proposed. Of all the

seismic gaps in North America, the Guerrero gap is among those most likely to have a great

earthquake. Its tectonic setting is remarkably similar to the setting in the Pacific northwest, and

thus directly relevant to US issues in earthquake engineering. A major earthquake in Guerrero

will be of great interest to see if the relatively low amplitudes of ground motions recorded in the

1985 Michoacan earthquake are repeated. If they are, confidence would increase in the

hypothesis that the low 1985 motions were not an anomaly, but that they can rather be used as a

basis for design.

The Mexican strong motion network is very sparse by the modern standards that have been set in

Japan and Taiwan. The scientists in Mexico are looking for ways to expand it. Figure 3.6.1

shows a map of the network as of October, 2006. The relatively high density of stations in

Guerrero (the state around Acapulco) is achieved by the Guerrero network, thanks to the support

of the National Science Foundation. This part of the Mexican network largely follows the

corridors with highest accessibility, along the coast and along the road from Acapulco to Mexico


City. Beyond this US contribution, several organizations in Mexico have installed strong motion

instruments to create the complete network shown in Figure 3.6.1. Conspicuous among these

organizations would be the Instituto de Ingeniería, Universidad Nacional Autónoma de México

(UNAM), the Centro Nacional de Prevención de Desastres, the Centro de Instrumentación y

Registro Sísmico, and the Comisión Federal de Electricidad, CFE). Mexico City was relatively

well-instrumented after the 1985 disaster. The extreme corner of northwest Mexico, outside of

the scope of Figure 1, which is affected by the San Andreas fault system, is monitored by Centro

de Investigación y de Educación Superior de Ensenada. The Fundacion Javier Barros Sierra

operates an alert system that is designed to detect a major earthquake in Guerrero and warn

Mexico City of the coming seismic waves.

The Guerrero network was among the first digital accelerograph networks to be established

anyplace in the world. The scientists and engineers of Mexico have shown outstanding

competence in maintaining the network, as a backbone of the entire Mexican network,

continuously since 1985. In the first 20 years, the 30 stations recovered over 3600 strong motion

records. The data provide an outstanding example of the magnitude dependence of strong

motions, and contribute critical pieces of information for understanding of the ground motion

hazard in Mexico City, one of the largest cities in the world. The network has also helped

invigorate the earthquake engineering community in Mexico, which is arguably the strongest

program in the western hemisphere south of the United States. This demonstrates how

successful international collaborative projects can be in providing data that is crucial to the

international effort to understand severe earthquakes.


Figure 3.6.1


3.7. The NSF George E. Brown Jr., Network for Earthquake Engineering Simulation (NEES) Jamison Steidl (University of California, Santa Barbara) Robert Nigbor (UCLA) and Les Youd (Brigham Young University)

NEES is a program funded through the Engineering Directorate of NSF. As a national shared-

use resource of 15 experimental facilities, NEES is meant to accelerate the pace of advances in

earthquake engineering research and facilitate the transfer of these advances to practice. As part

of this program, two permanent geotechnical strong motion arrays (GSMA) were constructed

and are maintained as one of these 15 experimental facilities. The GSMA facilities are meant to

improve our understanding of the effects of surface geology on ground shaking, permanent

deformation, and liquefaction. The insitu monitoring at these sites provides the observational

constraint data for the validation of empirical, analytical, and computational models that have

been developed to simulate dynamic soil response. In addition, one of the two permanent arrays

also includes an instrumented experimental structure to improve our understanding of soil-

foundation-structure interaction (SFSI).

The two permanent geotechnical strong motion arrays are located in Southern California, in a

seismically active region near the San Jacinto, Imperial, and San Andreas faults. The first site is

located in the mountains above Palm Springs in Garner Valley located between the San Jacinto

and San Andreas faults. The second site is located in the Imperial Valley just south of the Salton

Sea between the Imperial and San Andreas faults. There’s a relatively high probability of

observing significant ground shaking and the potential for liquefaction from moderate to large

earthquakes in this region within the 10-year operational period of the NEES program.

Instrumentation at these two sites include surface and borehole accelerometers, borehole pore

pressure transducers, water level and meteorological sensors, flexible displacement casings,

cross-hole casings, inclinometer casings, and surveyed benchmarks.

In addition to the ongoing passive monitoring of ambient noise and small and moderate events

(M1 to M5) since the sites became operational in the Fall of 2004, researchers have also been

conducting active testing at the sites. This includes using the NEES@UTA “T-Rex” vibroseis

truck to excite the ground at both sites. At the Garner Valley site, the instrumented experimental

structure also has a remotely operable shaker that can be used to excite the structure as well as


the ground beneath it. The data collected from running the shaker daily at Garner Valley is

providing researches with information about the effects of environmental conditions such as

temperature, water level, and soil saturation on structural response.

In addition to the NEES program, there are other active strong-motion monitoring programs at

UCSB. Two other geotechnical array facilities, the Borrego Valley Downhole Array and

Hollister Earthquake Observatory, are currently operated by UCSB. These were donated to

UCSB by the Japanese construction firm Kajima, and are similar in scope to the NEES sites, but

do not include liquefaction and structural monitoring. The Southern California Earthquake

Center (SCEC) also currently operates a borehole instrumentation program and portable

instrument center through funding to UCSB.

3.8 . Overview of other US programs and activities – Goals, Strategy, and Status Robert L. Nigbor (University of California, Los Angeles)

The primary emphasis of current strong motions is the collection of strong shaking data from

accelerometers on the ground and in structures for use in analyses after the earthquake. Results

are the raw time series data and strong motion parameters including SA, the spectral

acceleration. While this must continue to be a primary focus, monitoring for Situational

Awareness (the “Other SA”) is and will become another important reason for strong motion

monitoring.

Situational Awareness is a recent buzzword from the Human Factors field. It is heavily used in

the military, but has found its way into the lingo of natural disaster response & recovery. The

meaning is “knowing and understanding what is happening around you.“ As applied to

earthquake disasters, its meaning can include the knowing and understanding of shaking

intensity on the ground and in structures.

Current instrumentation technology allows the immediate provision of strong motion data and

information to remote users after and even during an earthquake. Information for situational

awareness purposes must be parameters and visual information, not raw time series data.

ShakeMap is a recent example. However, this concept is not new. Nuclear Power Plant seismic


instrumentation has been used for Situational Awareness for decades. Other examples exist with

specific dams, bridges, buildings, and utility systems.

We should consider this broad category of application when we discuss “Needs and

Opportunities” in this workshop.

Current Applications and Future Visions for Strong-Motion Research | 37

Chapter 4 Current Applications and Future Visions for

Strong-Motion Research

Special invited presentations were given by three distinguished individuals as a means of

stimulating the thinking of the workshop participants prior to their meeting in Working Groups.

These presentations looked at the needs for strong motion research from the perspective of an

academician, a practicing structural engineer, and a risk analyst. Extended abstracts of these

presentations are provided below. The complete PowerPoint version of each presentation is

contained on the CD-ROM attached to these proceedings. The reader is strongly encouraged to

examine these presentations in detail as they provide many important insights regarding current

application and future directions for strong motion research, and constitute the motivation for

many of the conclusions and recommendations of the Working Groups.

4.1 Current Applications and Future Visions for Strong-Motion Research: An Academic Perspective Gregory L. Fenves, Department of Civil and Environmental Engineering University of California, Berkeley

Research and application of strong-motion instrumentation and use of the data have been an

important aspect of the earthquake engineering field for the past half-century. Many of the

innovations in the area of strong-motion applications have grown from academic research at

universities. A few examples of groundbreaking research are response spectra, seismic hazard

assessment methods, spatial variation of ground motion, understanding of near-fault ground

motion, and regional loss assessment methods based on recorded and simulated ground motion.

One of the most important reasons for continued research in strong-motion instrumentation and

use of the data is that strong-motion data are absolutely essential in understanding the earthquake

hazard, the impact on the built-environment, and the development of effective earthquake risk

reduction engineering methods, designs, and policies. Three ongoing research programs

highlight the current and anticipated trends in the strong-motion field.

The first example of current research is the Lifelines Program of the Pacific Earthquake

Engineering Research (PEER) Center [1]. The Lifelines Program is a partnership between


university researchers and professionals in seismology, geotechnical engineering, and structural

engineering, working together on problem-focused research that is sponsored by industry and

government. The program has thrust areas that are directly related to strong-motion research,

including earthquake ground motion, site response, and permanent ground deformation. Other

relevant thrusts are network system seismic risk and emergency response. An important product

of the Lifelines Program is an extensive database that is one of the largest uniformly processed

strong-motion repositories in the world with more than 10,000 records from 173 earthquakes [2].

Another significant product of the Lifelines Program is the Next Generation Attenuation Models [3].

This is a collaboration of four modeling teams to define and use a common data set of strong

motion records and site classifications in the development of peer-reviewed attenuation

relationships for ground motion. The new attenuation relationships are now under review by the

U.S. Geological Survey for inclusion in the National Earthquake Hazard Maps.

A second area of active research is the design and application of micro-electromechanical

(MEMs) sensors in wireless networks for sensing, recording and processing earthquake ground

motion and the response of geotechnical and structural systems. These accurate, yet

inexpensive, sensors will eventually allow highly spatially dense recording of ground motion.

Sensors in networks with 1 km spacing or even less are possible using this new technology,

particularly if the networks are leveraged with wireless communication systems in urban areas.

Spatially dense instrumentation, far beyond what current technology allows, will revolutionize

understanding of the variability of ground motion and the impacts of site response, soil-structure

interaction, and structure-structure interaction. At UC Berkeley, an interdisciplinary group of

earthquake engineers, electrical engineers and computer scientists have developed and deployed

one of the largest wireless sensor networks on a long-span bridge. Some of the technical

challenges include high-rate sampling, time synchronization, reliable data transfer, and high data

volumes over a network that had more than 50 hops of low-power wireless communication of

data between nodes (Pakzad et al., 2005). The research has demonstrated that low-cost MEMs

can accurately sense motion and that reliable and scalable communication over multi-hop

networks is effective.


Another application of advanced sensor networks is on downhole arrays for understanding travel

path and local effects of ground motions on multiple scales. These networks have successfully

been used to detect and model liquefaction in earthquakes and a field test. An advanced

downhole instrument, named Terra-Scope, is under development at UC Berkeley by Professor

Steven Glaser (Chen et al., 2006). It includes six accelerometers (including a 24-bit high

resolution MEMs sensor), tiltmeter and compass with a 16-bit microcontroller, and 2Mb of

RAM, all enclosed in a 300 mm by 50 mm package for placement in a borehole. Terra-Scope

will be deployed in a 4D distributed seismic monitoring network with the smart downhole

sensors linked in a heterogeneous network to a local gateway.

The third area of research that is impacting the field of strong-motion is the move beyond

reliance on recorded ground motion to the simulation of ground motion based on first principles.

For example, Professor Jacobo Bielak’s research on TeraShake at Carnegie Mellon University as

part of the Southern California Earthquake Center (SCEC) is providing broadband simulation of

ground motion in the Los Angeles basin (Akcelik et al., 2003). Using validated models, these

simulations give unprecedented information about the ground motion that is expected in a large

earthquake. The simulations provide engineering design data about near-fault effects, large-

scale sedimentary basins and basin edge effects, and how topological features focus ground

motion.

In summary, three areas of research contribute to a vision for strong-motion research in the

future: (i) ubiquitous sensors at the ground surface and below the surface to provide spatially

dense data about ground motion and response of engineered systems, (ii) highly capable strong

motion databases to support data mining for earthquake engineering applications and suitable for

the scale of data recorded in dense strong-motion networks, and (iii) high-fidelity ground motion

simulations validated with spatially dense strong-motion data.

1 PEER Lifelines Program, http://peer.berkeley.edu/lifelines/ . 2 PEER Strong Motion Database, http://peer.berkeley.edu/smcat/ . 3 Next Generation Attenuation of Ground Motion (NGA) Project, PEER Lifelines Program,

http://peer.berkeley.edu/lifelines/nga.html .


4.2. Current Applications and Future Visions for Strong-Motion Research - A Practitioner’s Perspective Farzad Naeim, Vice President and General Counsel John A. Martin & Associates, Inc.

The purpose of this presentation is to demonstrate the vital rule of strong motion research in

advancement of earthquake engineering practice and the pivotal rule that it plays in improving

the seismic safety of the homes and offices we live in or work at. Perhaps the best way to

address this issue is to try to answer the following three key questions:

1. Why do we need strong motion data?

2. What are we doing with strong motion data today?

3. What should we do in the future?

The simple answer to the first question is that we need strong motion data because such data is

the only real link between our theories and reality. In addition, our theories, at least the theories

that form the basis of contemporary engineering practice do not correlate very well with the

realities. Several examples are provided to show this state of confusion. These examples

illustrate that there are various methods in use for scaling strong ground motion records for use

in performance-based design of buildings and these methods provide widely varying results.

This simply is not acceptable because if various approaches point the design engineer to wildly

various locations in the building as the “weak-point,” the reliability of engineer’s decision

making will not be reliable. We need further strong motion research to come up with a set of

rational and consistent methods to select, manipulate and use strong motion data in engineering

practice.

Other examples illustrate that the strength and stiffness values commonly utilized in design do

not correlate well with the values interpreted from recordings obtained from instrumented

buildings. Given the fact that building structures are very diverse in configuration, material

properties, workmanship and type and level of detailing implemented in them, it is very difficult,

if not impossible, to obtain the information necessary to improve the correlation between the

assumed values and real ones from a series of laboratory tests. There would not be nearly

enough financial resources and laboratories in the entire universe to let us perform the number of

tests necessary to achieve our objective. On the other hand, there exists an enormous laboratory


out there consisting of every building that is in function today. All we need to do is to

instrument as many of them as we can and harvest the results after each earthquake. In

California, there are only about 180 buildings, which are extensively instrumented. However,

over the past two decades, these instrumented buildings have provided the researchers and

engineers with a vast amount of knowledge regarding the actual behavior of buildings during

earthquakes and have been pivotal in narrowing the gap between our theories and the reality.

Imagine what a boost for seismic safety, cost-efficient design, and minimization of post-

earthquake interruptions would be gained if we had 1,000 or 10,000 buildings extensively

instrumented.

The answer to the second question is provided by examples of recent work by the author which

have been implemented in a software system recently released by state of California titled

CSMIP-3DV, continuation of which have resulted in reasonably reliable methods for accessing

post-earthquake safety evaluation of buildings remotely and instantaneously.

The answer the third question is even simpler. We should avoid making the same mistakes over

and over again. By neglecting the importance of strong motion research we have lost a window

of opportunity to better our theories, improve our design methodologies, and benefit the society

to the extent that we could have had if we have acted otherwise. We are at a historical juncture.

With continued support for strong motion research we are not far from being able to provide

continuous health monitoring of our precious infrastructure not only for earthquakes, but for

other natural and man-made disasters. We will be able to identify which buildings are damaged

and to what extent and what buildings can wait for an evaluation, within minutes following a

disaster. Can we afford to forgo such an opportunity? I think not.


4.3 Applications and Vision for Strong-Motion Research: a Risk Perspective Keith Porter California Institute of Technology

Introduction

Strong-motion instrumentation in buildings is primarily used to assess and improve structural

analysis, by enabling structural engineers to compare their models’ prediction of real buildings’

structural response with motions recorded by accelerometers. The advent of performance-based

earthquake engineering (PBEE) since the late 1990s has broadened the scope of the structural

engineers’ concerns to include physical damage to structural and nonstructural components, as

well as probabilistic system-level losses such as repair costs, casualties, and loss of use (“dollars,

deaths, and downtime”). PBEE tools and methods are entering general use, beginning with

FEMA 273 (BSSC 1997), FEMA 356 (ASCE 2000), and ASCE-31 (2003), and continuing with

next-generation PBEE methods promoted by the Pacific Earthquake Engineering Research

(PEER) Center and others (e.g., Porter 2000, Krawinkler 2005, Comerio 2005), now being

brought to professional practice by the Applied Technology Council with support by the Federal

Emergency Management Agency. With the broader scope of PBEE comes greater information

demands, particularly the development of probabilistic relationships between structural response

and physical damage to a wide variety of building components. This paper summarizes how

PBEE affects strong-motion instrumentation programs.

Overview of PBEE

It is useful to have a general understanding of PBEE. Second-generation PBEE methods

generally follow the information flow shown in Figure 4.3.1. Beginning at the left side of the

diagram, one defines the facility to be analyzed: its location, soil conditions, structural design,

and—new with the advent of PBEE—nonstructural design and number of occupants.


Site hazardλ[IM]

IM: Intensity measure,

e.g., Sa(T1)

Facility definition

D

Hazard analysis

Structural analysis

Structural model p[EDP|IM]

EDP: Engr demand param., e.g.,drift, plastic

rotation

D: Facility location &

design

Damage analysis

Fragility model

P[DM|EDP]

Damage response

λ[DM]

DM: Damage measure,

e.g., collapse, visible cracking

Loss analysis

Loss model

P[DV|DM]

Loss responseλ[DV]

DV: Decision

variable, e.g., repair cost

Hazard modelλ[IM|D]

Structural response λ[EDP]

Facility information

Decision:DVs okay?

Figure 4.3.1. Overview of PBEE

Hazard analysis. The first analytical stage is a probabilistic seismic hazard analysis (PSHA), in

which one quantifies the hazard function, generally as the mean frequency of exceeding various

levels of ground shaking intensity at a site of interest. PSHA methods are not described here.

Let the hazard function be denoted by λ[IM], where IM denotes the intensity measure. IM is

often in terms of 5%-damped elastic spectral acceleration response at a periods near the

estimated small-amplitude fundamental period of vibration of the structure of interest, although

other measures are used. One selects one or more levels of IM of interest (e.g., IM with 50%

exceedance probability in 50 yr, 10%/50 yr, 2% in 50 yr, etc., or alternatively a set of equally

spaced IM levels such as 0.1g, 0.2g, etc.). One then selects and scales ground-motion time

histories to match each level of IM. In sophisticated analyses, hazard deaggregation is

performed so that ground-motion time histories can be selected whose source magnitude,

distance, ε, and site classification approximately match the dominant sources at each IM level.

Structural analysis. In the next analytical stage, structural model is created of the facility of

interest, and nonlinear dynamic analyses performed using the ground-motion time histories

produced from the hazard analysis. These analyses produce estimates of the member forces and

deformations (collectively referred to as engineering demand parameters, or EDPs). Some

PBEE analyses have employed a deterministic structural models (e.g., Krawinkler 2005), while

others have accounted for uncertainties in mass, damping, and force-deformation behavior (e.g.,

Porter et al. 2002). The result is an estimate of the probability of exceeding various levels of

EDP given an IM level, denoted here by G[EDP | IM]. (Conditioning on facility design, D, is

implicit in all subsequent calculations). Denoting the first derivative of the hazard function with


respect to IM by λ΄[IM] and applying the theorem of total probability results in an estimate of the

mean frequency with which various levels of EDP are exceeded: [ ] [ ]

IM

EDP G EDP IM IM dIMλ λ′= ⎡ ⎤⎣ ⎦∫ (1)

Some researchers distinguish global collapse from other EDPs, and express EDP using

[ ]

[ ] [ ]

,IM

IM

EDP NC G EDP IM NC IM dIM

C P C IM IM dIM

λ λ

λ λ

′⎡ ⎤ = ⎡ ⎤⎣ ⎦ ⎣ ⎦

′= ⎡ ⎤⎣ ⎦

∫

∫ (2)

where NC denotes the event of no collapse, C denotes the event of collapse, and P[C|IM]

denotes collapse probability at a given level of IM.

Damage analysis. This is the point at which 2nd-generation PBEE exceeds traditional structural

engineering practice, and where new demands are introduced to strong motion research. Given

the structural response EDP to which each damageable structural and nonstructural component is

exposed in a given earthquake, one calculates the probability distribution of each component’s

damage state, using probabilistic relationships called fragility functions. Let P[DM ≥d| EDP=x]

denote the probability that a given component will reach or exceed damage state d given than it

is exposed to structural response equal to x; this is a fragility function. It is convenient (and for

several reasons common and theoretically valid) to idealize such fragility functions with a

lognormal cumulative distribution function (CDF). The probability that a component is in

damage state d is then given by

( )

( ) ( )

( )

1

1

1

1

ln1 0

ln ln1

ln

d d

d d

N

N

xP DM d EDP x d

x xd N

xd N

θβ

θ θβ β

θβ

+

+

⎛ ⎞⎡ = = ⎤ = − Φ =⎜ ⎟⎣ ⎦

⎝ ⎠⎛ ⎞ ⎛ ⎞

= Φ − Φ ≤ <⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎛ ⎞

= Φ =⎜ ⎟⎝ ⎠

(3)

where Φ denotes the standard normal CDF, θd and βd denote the median and logarithmic

standard deviation of the fragility function for damage state d, and N denotes the number of

possible damage states (in addition to the undamaged state). Figure 4.3.2 illustrates a simple

case with N = 2.


Figure 4.3.2. Example fragility functions for gypsum wallboard partition (Porter 2000)

Loss analysis. In the loss analysis, one calculates loss (e.g., dollars, deaths, or downtime) given

the results of the damage analysis. Methods have been developed to estimate each of these. For

example, to estimate repair cost, let Njd and Cjd denote the number and unit repair cost,

respectively, of components whose type is indexed by j that experience damage state d. The unit

cost Cjd would typically be tabulated for a reference location (a city or a national average, for

example) in a reference year. Let CI denote a factor to account for inflation and CL a factor to

account for location (i.e., construction costs in the location of interest, relative to the reference

location). Let COP denote a factor to account for general conditions and contractor overhead and

profit, and let V denote the replacement cost of the facility. Then total repair cost can be

estimated by

( )1 OP jd jd I L

j d

C C N C C C nocollapse

V collapse

= +

=

∑∑ (4)

Propagating uncertainty. There are a number of uncertain variables in a PBEE analysis: IM, the

ground-motion time history for a given IM, structural parameters such as masses, damping ratio,

member force-deformation behavior, etc. Various means have been developed to propagate

these uncertainties through the analysis, to produce probabilistic estimates of future loss,


including various simulation approaches, sometimes combined with close-form calculation in the

damage and loss analyses.

Developing fragility functions

The mathematics for creating component fragility functions has been established to deal with

damage data of several types (Porter et al. 2007):

Actual EDP at which damage occurred in specific components. These data typically come from

laboratory tests, where researchers control the EDP and observe damage as the test progresses.

Bounding EDP, i.e., the maximum EDP to which components were subjected, and whether the

components were damaged (even if the damage occurred at lass than the maximum EDP). This

kind of data commonly come from earthquake experience, where nobody observes the exact

level of excitation that caused a particular component to fail, and where some components fail

and others do not. Strong motion instrumentation programs could provide these data.

Capable EDP, i.e., evidence that components have experienced known levels of excitation

without being damaged. These data commonly come from seismic qualification tests of valuable

equipment used in energy facilities.

Updating. Damage data sometimes become available after a fragility function has been

established. Bayesian updating can be used to improve existing fragility functions using the new

information. Strong motion instrumentation programs could provide these data as well.

How strong-motion instrumentation programs fit into PBEE

Fragility data. As noted above, the math to create fragility functions is available; what is needed

is the damage information. Major gaps remain in the dataset needed for a damage analysis: only

about 20% of the roughly 275 categories of building components listed in NISTIR 6389 (NIST

1999) have any fragility functions. The data required to fill this gap generally include the

number of components of a given taxonomic group exposed to strong motion (in a given

building or set of buildings, for example), the EDP to which each was exposed (the interstory

drift, for example), and the damage state of each. The mere fact that some number of


components were damaged in a particular building in a given event is meaningless without the

other two data items: how many were there and what level of excitation did they experience?

Strong motion instrumentation programs have historically informed and improved structural

analyses and to some extent hazard analysis, but could provide this additional information.

Attention to building components as well as structure type. Strong motion instrumentation

programs could inform the future development of PBEE by ensuring that exposure and damage

quantities were available after earthquakes for a wide variety of common building components.

That means that the decision of which buildings to instrument should include what kind of stuff

is in them, in addition to what structural systems they use.

Access to exposure data. As already noted, for damage data to be useful, all three of quantities—

number exposed, number damaged, and EDP—must be available. Number of structural

components is already available, since structural drawings are typically acquired for

instrumented buildings. Some nonstructural components change over time, for example as

tenants remodel interior finishes. It would therefore be valuable for strong motion

instrumentation programs to institute procedures for researchers to access instrumented buildings

after earthquakes and gather the necessary quantities.

Instrument adjacent floors. Strong motion instrumentation programs can help to inform PBEE by

citing instruments so that the variety of relevant EDPs is available. Since structural members

tend to be most sensitive to member forces and deformations (curvature, shear deformation, etc.),

it would be valuable for PBEE development if strong motion instrumentation programs began to

include sensors that directly measure deformation quantities. Since many nonstructural

components are drift-sensitive, it would be valuable to deploy accelerometers or instruments that

directly measure displacement on adjacent floors.

Another challenge that strong motion instrumentation programs could address is damage

correlation: to what extent is failure probability affected by proximity of components,

construction by the same or different contractors, and other factors? Strong motion

instrumentation programs could begin to address this question by citing instruments in many

different buildings with similar components.


Isn’t this NEES’ job?

The George E Brown Network for Earthquake Engineering Simulation (NEES) is an earthquake

engineering collaboratory, i.e., it comprises seismic testing facilities at universities around the

country, linked by an advanced cyberinfrastructure. NEES is expensive: approximately $80

million has been spent on new experimental facilities, and $20 million per year is currently spent

on their maintenance and operation. Approximately $10 million is spent annually on actual

research, i.e., to purchase or construct test specimens and to pay researchers salaries and other

expenses. Because of the high capital and maintenance costs, and relatively limited research

budget, components that are tested tend to be sophisticated, potentially revolutionary—in a

word, sexy—rather than those that contribute heavily to actual earthquake repair costs. NEES

researchers tend not be interested in or receive funding to conduct experiments on common

exterior and interior finishes, mechanical and electrical systems, and furnishings that usually

break, overturn, or otherwise result in earthquake repair costs, downtime, and injuries. Even if

these topics were of interest, NEES research budgets and schedules do not permit testing of the

large numbers and variety of components necessary to create robust fragility functions, or to deal

with damage correlation. NEES will not solve the fragility problem; at least not alone.

Conclusions

The current focus of strong motion instrumentation programs tends to be on system-level

structural performance. New PBEE methods are bringing component-level damage and loss

within the structural engineer’s domain, including both structural and nonstructural components.

A major gap exists in the fragility data required to perform damage analysis for most of these

components. NEES is unlikely to fill a large part of that gap, the part having to do with

relatively mundane components in existing buildings. Strong motion instrumentation programs

can help to fill this gap, by installing the kinds of instruments required to record the excitation

that earthquakes impose on ordinary components in existing buildings, and by supporting the

post-earthquake inspections necessary to observe and record damage to common building

components.

Working Group Findings | 49

Chapter 5 Working Group Findings

Working Group Findings Workshop participants were assigned to one of three Working Groups, which met for

approximately 4 hours to discuss strong motion research needs and opportunities. The Working

Groups were asked to identify and flesh out a few high priority research efforts rather than

present a long laundry list of possible research activities. Each research effort was to be

supported by a statement of research goals, the rationale or justification for the research, and a

strategy for achieving the stated goals.

5.1 Working Group 1 Chair: Bret Lizundia Recorder: Jacobo Bielak Assigned Working Group Members: Brad Aagaard, Craig Comartin, Craig Davis, Gregory Fenves, Moh Huang, Sami Masri, Keith Porter, and Jamison Steidl

5.1.1. Major Issues Considered

• It was generally agreed that there is a need for more instrumental recordings to understand the behavior of the earth and engineered civil systems during various levels of ground motion.

• Who can we get to pay for increasing the quantity and quality of sensors being deployed? How can we spur private development, rather than rely only on a limited amount of agency funding?

• What strategies are both valuable and likely to be funded?

• We need to think holistically about the interdependency of infrastructure both in how resources should be allocated and in providing opportunities for mutual benefit.

5.1.2. Increasing Sensor Usage

• Goal: Show the cost effectiveness of sensor technology to spur increased investment.

• Rationale: Private capital can be used to augment agency funding of instrumentation if the return on investment opportunities can be shown more clearly.

• Strategies:

- Research the cost effectiveness of instrumenting selected beam-column joints with displacement sensors in welded steel moment frame buildings with Pre-Northridge earthquake connections vs. post-earthquake disruptive investigation.


- Link measurable engineering demand parameters (like drift) to damage as an incentive for insurers to pay out faster and more objectively.

- Investigate opportunities for leveraging existing sensors of other disciplines, such as building energy management monitoring.

- Demonstrate how sensors can be used for improved emergency response: Do we need to evacuate? Do responders need to be sent to the building? Do we need to close the building?

- Develop sensor technologies appropriate for implementation during new construction, not just existing buildings.

5.1.3. Optimizing Sensor Usage on a Local Scale

• Goals: Determine the optimum type, number, and configuration of a sensor array for a particular objective.

• Rationale: As the cost of sensors drops and as the number of types of sensors increases, we need to more carefully consider appropriate resource allocation.

• Strategies:

- Study past recordings to determine the most effective locations of sensors in providing useful results.

- Increase the databases of damage and performance information for structures with instrumental recordings.

- Conduct experimental research using strong motion records to provide missing links between engineering demand parameters and performance and damage measures for selected components.

- Conduct tests using different types of sensors to examine their effectiveness in measuring desired parameters.

- Develop new methods and technologies for measuring deformation fields, rather than acceleration.

- Instrument nonstructural components.

5.1.4. Optimizing Sensor Usage on a Global Scale

• Goals: Employ instruments to achieve multipurpose usage for urban infrastructure systems.

• Rationale: The urban environment is made up of many engineered, social, political, etc. systems that must be managed in post-earthquake disaster conditions.

• Strategies: Develop concepts, framework, and prototypical examples for integrated instrument arrays and processing tools to provide decision makers the information needed to make decisions for post-earthquake emergency response and for prioritizing post-disaster recovery efforts. These same instrument arrays will be used to improve the


understanding of urban infrastructure performance and modeling capabilities. Strategies include:

- Instrument appropriate urban infrastructure and lifeline systems.

- Develop key information that can be rapidly extracted for emergency decision- making.

- Assess potential socioeconomic impacts related to probable facility damage and prepare plans for responding to potential impacts (multidisciplinary).

5.1.5. Enabling Methodologies for Dense Embedded Sensor Networks

• Goal: Cost effective free field and structural monitoring.

• Rationale: The emergence of dense embedded sensor networks presents new challenges for system design and data management.

• Strategies:

- Sprinkle the earth with smart dust.

- Develop improved designs for system architecture.

- Develop new algorithms to process the data.

- Develop/implement new methods for harvesting power for sensors, such as ambient vibration and solar.

5.1.6. Understanding Spatial Variability of Ground Motion and its Relation to the

Source

• Goals:

- To understand effects of propagation path, site effects, and the urban environment on ground motion.

- To understand variability of ground motion in the near field with fault rupture behavior.

- To understand differences in ground shaking between great and strong earthquakes.

• Rationale:

- The extent to which surficial layers, basin effects, edge effects, and fault rupture processes affect spatial variability of free-field ground motion is still not well-understood.

- It is known that for a single structure with a large footprint, ground motion with wavelengths comparable or smaller than the base dimensions of the structure can be significantly reduced with respect to the free-field motion. Does a collection of buildings act similarly to a single larger one in filtering ground motion?


- Our predictive capabilities for very large earthquakes are still very poor, partly from lack of data.

- Ground motion at a given distance due to a magnitude MW 8 earthquake can be smaller than that due to a weaker earthquake. The causes are still not well-known.

• Strategies:

- Increase the number of accelerographs at select near-fault regions.

- Place instruments at foundation level within a block of buildings in an urban environment, and also at nearby empty lots.

- Instrument also other stories to study performance of entire system of buildings, and for verification and validation of simulations.

5.2 Working Group 2

Chair: Andrew Whittaker Recorder: Mark Sinclair

Assigned Working Group Members: Roger Borcherdt, Ahmed Elgamal, Thomas Heaton, Anne Kiremidjian, Nico Luco, Robert Reitherman, and Yi-Ben Tsai

5.2.1. Missed Opportunities In the absence of integrated dense arrays of geo and structural sensors, we cannot

• Protect the homeland

• Monitor the service and extreme-event response of mission-critical infrastructure

• Enable and validate high fidelity tools and models for performance based design and ground motion simulation

• Conduct real-time damage assessment for response, occupancy and recovery to reduce physical and economic losses

• Conduct realistic scenario planning for the next great earthquake

5.2.2. A Proposal – The 1000/100/10 Initiative

• Deploy dense, integrated arrays of sensors in the built and geo environments across urban regions at low cost

- 1000 instruments per structure/geosystem

- $100 each

- 10 years

• Total estimated cost: $250 M USD

• Multidisciplinary management structure - Leadership by the earthquake engineering and earth science communities


5.2.3. Outcomes of the initiative • Real-time computation of damage, occupancy, loss and time to full recovery (diagnosis

and prognosis)

- Local and regional

- Real and scenario events

• Robust data sets for societal planning

• Enable performance-based engineering

- Correlation of response and damage level

- Examine utility of current codes and guidelines

- Improved fragility and loss functions

• End-to-end simulation

- Model response from fault rupture through economic loss

- Validated and integrated models for geo and structural response

- Validated deterministic simulation codes

5.2.4. Research Needs and Opportunities

• Sensor and sensor arrays

- wireless

- GPS

- strain gages

- optical

- direct displacement measurement

• Databases

- Data structures

• Consistent formats for geo and structural data (BIM)

• Open architecture

• Structural information

- Metadata

- Curation and mining

• Component models and material models based on full-scale performance data

- Link to NSF NEES program

- Structural and geo models


- Ground motion models

• Integrated analysis platforms

- Geo and structural components and systems

- End-to-end simulation tools

• Validate existing tools for PBEE

- Linkages between demand parameters (e.g. drift) and occupancy

5.2.5. Miscellaneous

• Develop the public policy to mandate instrumentation for improved emergency response.

• Periodically document the evolving historical context for public policy and technical communities

• Track growth in instrumented structures and geo-systems (e.g. as percentage of inventory)

• Retrospective scenario planning (e.g. Northridge)

• Acknowledge and support existing programs including CSMIP, ANSS, etc.

5.3 Working Group 3 Chair: James Beck Recorder: James Goltz

Assigned Working Group Members: John Anderson, C. B. Crouse, Naeim Farzad, Robert Nigbor, William Savage, and Anthony Shakal

5.3.1. Research Priority 1: • Goal – Increase the probability of capturing S-M data from M≥7 worldwide.

• Rationale – Major earthquakes are infrequent and represent a gap in our knowledge, especially in the near field, and may occur in unmonitored regions.

• Strategies

1) Develop low lifecycle cost instrumentation that is suitable for international deployment with long-term unattended operation.

2) Deploy mobile arrays according to pre-existing protocols worldwide.

3) Convene an international workshop to secure agreement on locations, their priorities in order to enhance the probability of capturing large earthquakes, and possible funding sources for instrumentation of the chosen locations.

• Possible Responsible Agencies:

- For workshop: COSMOS, World Seismic Safety Initiative, IASPEI, IAEE


- For instrumentation: UN, state geology and/or seismology agencies in each chosen country.

5.3.2. Research Priority 2 • Goal – Improve methods of assessing inter-story drift and other relevant parameters to

establish structural performance during earthquakes.

• Rationale – Accelerations are an indirect method of measuring inter-story drift and other performance-related parameters. It is important to find ways to measure inter-story drift and other relevant performance parameters directly or indirectly, but with higher confidence, using other sensor types and improved analysis methods.

• Strategies

1) Consider other sensors including GPS, strain gauges and displacement sensors such as lasers,

2) Experimentally assess the accuracy of inter-story drift as calculated by accelerometers,

3) Capture structural health monitoring data before and after an earthquake.

• Responsible Agencies

- NSF or NIST/NEHRP funded research projects for strategy 1) and 3).

- NSF/NEES for strategy 2)

5.3.3. Research Priority 3

• Goal – Place more emphasis on monitoring of active faults in the US.

• Rationale – Recently, there has been considerable emphasis on the strong-motion monitoring of urban areas (e.g. ShakeMap in California). However, it is important that we not miss capturing strong-motion data in the near field of large earthquakes that will occur in the US.

• Strategies – Prioritize the selection of active faults and other active source zones for S-M monitoring, possibly through a workshop, which should also set goals for instrument density and placement. Also, consider new low-cost instruments requiring minimal maintenance that are useful for remote regions.


- ANSS, CSMIP, SCEC and COSMOS (to organize the workshop).


5.3.4. Research Priority 4 • Goal – Continue to improve access to S-M data and corresponding metadata.

• Rationale – Users need clearly identifiable gateways to all available S-M raw data and available products for rapid post-processing of the data. Organizations that contribute S-M data have shown the utility of such gateways.

• Strategy

- Sustain existing gateways like COSMOS VDC and NCESMD to serve as the clearinghouse for S-M data dissemination with due recognition for data contributors.

- Develop and improve software tools for data utilization and data mining.


- USGS, CGS, CA OES and COSMOS

References | 57

Chapter 6 References

Akcelik, V., J. Bielak, G. Biros, I. Epanomeritakis, A. Fernandez, O. Ghattas, E. Joong Kim, J. Lopez, D. O'Hallaron, T. Tu, and J. Urbanic, “High Resolution Forward and Inverse Earthquake Modeling on Terasacale Computers,” SC2003, Phoenix, AZ, November, 2003. (ASCE) American Society of Civil Engineers, 2000. FEMA-356: Prestandard and Commentary for the Seismic Rehabilitation of Buildings, Washington, DC, 490 pp. (ASCE) American Society of Civil Engineers, 2003. SEI/ASCE 31-03: Seismic Evaluation of Existing Buildings, Washington, DC, 444 pp.Chang, 2000 (BSSC) Building Seismic Safety Council, 1997, FEMA-273: NEHRP Guidelines for the Seismic Rehabilitation of Buildings, Federal Emergency Management Agency, Washington, DC, 386 pp. Chang, C.P. (2001). Reconstruction de la croissance d’une chaine de montagnes: le Sud de Taiwan, Ph.D. dissertation, Universite P. & M. Curie (Paris VI), France, 359pp. Chen, M., S.D. Glaser, and T. Oberheim, "Terra-Scope - A MEMS-based Vertical Seismic Array," Smart Structures & Systems, Vol. 2, No. 2, February 2006, pp. 115-126. Chao, H.L. (2000). A study of strong ground motion data from the 1999 Chi-Chi, Taiwan earthquake sequence, M.S. dissertation, National Central University, Taiwan. Comerio, M.C., ed. 2005. PEER Testbed Study on a Laboratory Building: Exercising Seismic Performance Assessment, Pacific Earthquake Engineering Research Center, Report 2005/12, University of California, Berkeley, CA Huang, B.S. (2001). Evidence of azimuthal and temporal variations of the rupture propagation of the 1999 Chi-Chi, Taiwan earthquake from dense array observations, Geophys. Res. Lett., 28, 3377-3380. Iwan, W. D., Ed., "Strong-Motion Earthquake Instrument Arrays," Proceedings of the International Workshop on Strong-Motion Earthquake Instrument Arrays, Honolulu, Hawaii, May 2–5, 1978. Iwan, W. D., ed., "U.S. Strong-Motion Earthquake Instrumentation," Proceedings of the U.S. National Workshop on Strong-Motion Earthquake Instrumentation, April 12–14, Santa Barbara, California, 1981. Kashima, T., 2000. Strong Earthquake Motion Observation in Japan. State of Art Lecture,

http://iisee.kenken.go.jp/staff/kashima/soa2000/soa.htm.


Krawinkler, H., ed., 2005. Van Nuys Hotel Building Testbed Report: Exercising Seismic Performance Assessment, Report 2005-11, Pacific Earthquake Engineering Research Center, Richmond, CA Lee, J.C., H.T. Chu, J. Angelier, Y.C. Chen, J.C. Hu, C.Y. Lu, and R.J. Rau (2002). Geometry and structure of northern surface ruptures of the Mw=7.6 Chi-Chi, Taiwan earthquake: influence from inherited fold belt structures, Jour. Struct. Geol., 24, 1, 173-192. Lee, C.T., C.T. Cheng, C.W. Liao, and Y.B. Tsai (2001). Site classifications for Taiwan TSMIP strong motion stations, Bull. Seism. Soc. Am., Dedicated Issue on the Chi-Chi, Taiwan Earthquake of 20 September 1999, 91, 5, 1283-1297. Lee, C.P., Y.B. Tsai, and K.L. Wen (2006). Analysis of nonlinear site response using LSST downhole accelerometer array data, Soil Dyn. Earthq. Eng., 26, 435-460. Mori, A.W., and C.B. Crouse, 1981. Strong Motion Data from Japanese Earthquakes. World Data Center A for Solid Earth Geophysics, Report SE-29. Next Generation Attenuation of Ground Motion (NGA) Project, PEER Lifelines Program, http://peer.berkeley.edu/lifelines/nga.html (NIST) National Institute of Standards and Technology, 1999. UNIFORMAT II Elemental Classification for Building Specifications, Cost Estimating, and Cost Analysis, NISTIR 6389, Washington, D.C., 93 pp. Pakzad, S.N., S. Kim, G.L. Fenves, S.D. Glaser, D.E. Culler, and J.W. Demmel, “Multi-purpose Wireless Accelerometer for Civil Infrastructure Monitoring,” Structural Health Monitoring 2005, Proceedings of the 5th International Workshop on Structural Health Monitoring, ed. F-K Chang, Stanford University, Stanford, CA, September 2005. PEER Lifelines Program, http://peer.berkeley.edu/lifelines/ . PEER Strong Motion Database, http://peer.berkeley.edu/smcat/ . Porter, K.A., 2000. Assembly-Based Vulnerability of Buildings and its Uses in Seismic Performance Evaluation and Risk-Management Decision-Making. Doctoral Dissertation, Stanford University, Stanford, CA, and ProQuest Co., Ann Arbor, MI, pub. 99-95274, 196 pp. Porter, K.A., J.L. Beck, and R.V. Shaikhutdinov, 2002. Sensitivity of building loss estimates to major uncertain variables, Earthquake Spectra, 18 (4), 719-743 Porter, K.A., R.P. Kennedy, and R.E Bachman, 2007. Creating fragility functions for performance-based earthquake engineering. Earthquake Spectra. 23 (2), May 2007Shin and

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Appendix A Workshop Agenda

NSF-CUREE WORKSHOP ON STRONG-MOTION RESEARCH NEEDS AND OPPORTUNITIES

Oakland Marriott, Oakland, California October 19-20, 2006

Agenda

Clavin Simmons Ballroom, 2nd Floor

Thursday, Oct. 19, 2006

7:30 Continental Breakfast

8:00 Welcome and overview of the workshop – Wilfred Iwan (Caltech)

8:15 Overview of major US programs – Goals, Strategy, and Status

• CSMIP – Anthony Shakal (California Geological Survey)

• ANSS – William Savage (U.S. Geological Survey)

8:55 Overview of other programs and activities – Goals, Strategy, and Status

• NEES – Jamie Steidl (UC Santa Barbara)

• Other US programs – Robert Nigbor (UCLA)

• Japan – C. B. Crouse (URS Corp.)

• Taiwan – Yi-Ben Tsai (Pacific Gas and Electric)

• Mexico – John Anderson (Univ. of Nevada-Reno)

• China – Moh Huang (California Geological Survey - CSMIP)

10:40 Break

11:00 Current Applications and Future Visions for Strong-Motion Research

• An Academic Perspective – Greg Fenves (UC Berkeley)

• A Practitioner’s Perspective – Farzad Naeim (John A. Martin & Assoc.)

• A Risk Perspective – Keith Porter (Caltech)

12:00 Introduction to afternoon session – Assignment and Charge to Working Groups

12:15 Break for lunch

12:30 Lunch (Room 210/11, on 2nd Floor)

Appendix A – Workshop Agenda | 61

1:30 Working Groups on Research Needs and Opportunities

Breakout Rooms: Calvin Simmons Ballroom, sectioned

Working Group 1, assigned Plenary Room (1&2)

Chair: Bret Lizundia, Recorder: Jacobo Bielak

Working Group 2, assigned Room 3

Chair: Andrew Whittaker, Recorder: Mark Sinclair

Working Group 3, assigned Room 4

Chair: Jim Beck, Recorder: James Goltz

3:00 Break

3:20 Working Groups (continued)

5:00 Free Time

5:20 Dinner off site arranged for those interested

Friday, Oct. 20, 2006

7:30 Continental Breakfast

8:00 Working Groups (review and finalize reports)

9:15 Break

9:30 Reports from Working Groups

10:30 Plenary Discussion

11:00 Summary and Closing

11:30 Adjourn and hotel check-out

12:30 Box Lunches will be arranged for those interested (Room 210/11, on 2nd Floor)


Appendix B Workshop Photos

Bill Iwan giving the introduction to the Strong Motion workshop.

[Shown standing left to right] Anne Kiremidjian, Brad Aagaard, Yi-Ben Tsai, Bob Nigbor, Sami Masri, Craig Comartin, Jacobo Bielak, James Beck, Keith Porter, Gregory Fenves, Andrew Whittaker, Mark Sinclair, Farzad Naeim, Ahmed Elgamel, Bret Lizundia, Craig Davis, Thomas Heaton, John Anderson, Anthony Shakal, Roger Borcherdt, Nico Luco, Moh Huang, C. B. Crouse, and Jamison Steidl [kneeling front] James Goltz, William ”Woody” Savage, Wilfred Iwan, and Robert Reitherman

proceedings of the nsf-curee workshop on strong-motion ... · ahmed elgamal, university of...

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