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CaliforniaEarthquake

Center

Southern California Earthquake Center

Southern California Earthquake Center Quarterly Newsletter, Vol. 2, No. 3, Fall, 1996.

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he Southern California Earthquake Center (SCEC) activelycoordinates research on Los Angeles region earthquake hazardsand focuses on applying earth sciences to earthquake hazardreduction. Founded in 1991, SCEC is a National Science Founda-tion (NSF) Science and Technology Center with administrative andprogram offices located at the University of Southern California.It is co-funded by the United States Geological Survey (USGS).The Education and Knowledge Transfer programs are co-fundedby the Federal Emergency Management Agency (FEMA). TheCenter’s primary objective is to develop a “Master Model” ofearthquakes in southern California by integrating various earthscience data through probabilistic seismic hazard analysis. TheSCEC promotes earthquake hazard reduction by:

• Defining, through research, when and where future damaging

From the Center Directors...From the Center Directors...From the Center Directors...From the Center Directors...From the Center Directors...

Center Director Science Director

What Is the Southern California Earthquake Center? earthquakes will occur in southern California;• Calculating the expected ground motions; and,• Communicating this information to the public.

To date, SCEC scientists have focused on the region’s earthquakepotential. Representing several disciplines in the earth sciences,these scientists are conducting separate but related researchprojects with results that can be pieced together to provide someanswers to questions such as where the active faults are, how oftenthey slip, and what size earthquakes they can be expected toproduce. Current work focuses on seismic wave path effects andlocal site conditions for developing a complete seismic hazardassessment of southern California.

Information: Call 213/740-1560 or e-mail [email protected]

T

Thomas L.

O

The Dilemma of

Federal Funding

ver the last twenty years, support for earthquake research insouthern California has come largely from the federal govern-ment. Federal dollars from US Geological Survey (USGS) andNational Science Foundation (NSF) programs have supported asignificant amount of basic earthquake science research, as well asthe establishment of important seismological facilities such as theSouthern California Seismic Network and, more recently, SCEC.

It now appears that with yet another infusion of dollars from boththe federal government and the private sector, we will see aquantum jump in our seismological infrastructure as the newGlobal Positioning System (SCIGN) and broadband seismological(TERRAscope) networks come on line over the next few years.These facilities will be multi-million dollar activities, involvinghardware acquisition, operations, and maintenance.

But with deficit reduction taking center stage in Washington,priorities constantly shifting, and funds for basic researchdwindling, will we be able to take full advantage of these newfacilities — i.e., will we be able to do the necessary science whileat the same time keeping the networks state-of-the-art and fullyoperational? Much will depend on SCEC’s efforts, as well as the

earthquake research community pulling together and becomingmore proactive, both collectively and individually, in seeking thenecessary resources.

Specifically, we must work with the State of California. SCEC andthe new GPS and seismic networks are important additions to theState’s arsenal for earthquake hazard assessment and disasterresponse and recovery, yet few State dollars support theseinitiatives. The California Division of Mines and Geology, theCalifornia Seismic Safety Commission, and the California Councilon Science and Technology all recognize the need for more Stateresources. We must find ways to support their efforts on ourbehalf, and on behalf of a more advanced and sustainableearthquake science and engineering effort in California. ♦

Tom Henyey


Sixth Year Site Review Report

See "Review" on Page 4

uring a three-day, sixth-year review in late August,SCEC hosted a Visiting Committee from the NationalScience Foundation (NSF) and the United States Geologi-cal Survey (USGS). Members of the Site Visit Committeeincluded James Beavers (MS Technology Inc.), GeorgeDavis (University of Arizona), Karen Fischer (BrownUniversity), Carl Kisslinger (University of Colorado),Charles Langston (Pennsylvania State University),Francis Wu (SUNY at Binghamton), and JamesWhitcomb (NSF Program Director for Geophysics).

This was a critical milestone for the Center in that theresults of the review will define, in essence, where we goin the next five years. SCEC directors, group leaders,scientists and student interns presented a formaloverview and poster session highlighting both theCenter’s current scientific and outreach activities andour future plans.

SCEC Representatives Host Site Review Teamat University of Southern California Campus

D Before the site visit, SCEC directors conducted a self-review using the Center’s own demanding criteria. TheCenter’s original goals of promoting scientific research inearthquake hazards, integrating results using the mastermodel, and communicating research results to end usershas proven relevant, based on positive responses fromearth scientists, engineers, and end users in the commu-nity-at-large. The Site Visit Committee concurred withthis assessment.

SCEC’s strengths in research integration continue to beevident in master model construction (see Figure 1,Master Model). The Center’s Phase II report, (“SeismicHazards in Southern California: Probable Earthquakes,1994-2024,”), the soon-to-be-released Phase III report(which will include path and site effects), and the mastermodel data bases maintained at various SCEC institu-tional sites are three examples. In addition, the Center-

The master model has had asignificant impact in theearthquake scientific and hazardassessment communities, judgingfrom hundreds of inquiries fromscientists outside SCEC, and salesof thousands of copies of thePhase II report. Master modelproducts and data are being usedby the State and national hazardmapping programs, consultinggeologists for ground motionprediction, local government forvariable seismic zonation, and theinsurance industry for risk analysis.This master model was the firstversion created in 1991, beforeCenter scientists solicited feedbackfrom end users. The master modelwill be reconfigured at the 1996Annual Meeting, to reflect changesin both the scientific and educationand outreach approaches.

Other National & International Data Bases (Geology, Gravity, Heat Flow, etc.)

University & Government Research

Visitors

Instrumentation, Deployment Strategies, Special Studies

Integration & Master Model Updates

3-DStructure Model

Deformation & Stress Models

Strong Ground Motion Prediction

Testing of Possible Precursors

Synthesis, Time-DependentProbabilities & Hazard Maps

LabData

Geophysical Surveys

Permanent & TemporarySeismic networks

Earthquake Geology & Neotectonics

Geodetic data

Structure Imaging (V,Q,..)

RegionalKinematics & Geometry

Fault-Specific Mechanics & Dynamics

Seismicity Analysis &Simulation

Mathematical & Statistical Framework

Data Bases, Data Center

Scientific Response

Users;Public, Engineers, Policy Makers

THE MASTER MODEL



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Review continued from Page 3 ...

See "Report" on Page 5

sponsored bibliographyincludes over 336 publicationsas of mid-1996. Most arerefereed publications inpremier journals.

The Site Visit Committeerecognized that both scientificand end user interactions areindications of the Center’sstrength. Scientific workshops,seminars, and group andannual meetings have pro-vided rich forums for discuss-ing data and new ideas.Workshops involvinggeotechnical engineers haveresulted in effective cross-disciplinary dialogue on issuessuch as ground motionprediction, non-linear siteeffects, and probabilisticseismic hazard analysis. The“C-Cubed” program (Caltransand the City and County of LosAngeles), is one example ofhow working relationshipsbetween engineers and earthscientists can be successful.Also noted by the Site VisitCommittee are the effectiveworking relationships theCenter has developed with theUSGS, the California Divisionof Mines and Geology(CDMG), the CaliforniaSeismic Safety Commission,the Governor’s Office ofEmergency Services, localgovernments, and other specialinterest groups. In addition,numerous workshops, semi-nars, and field trips areregularly held for various usergroups.

The Center publishes thisquarterly newsletter andanticipates stepping up itspublishing activities in the nextfive years. We have clearlyincreased earthquake aware-ness in southern California

through our distribution of“Putting Down Roots inEarthquake Country,” thePhase II report, and spots onradio and television.

A significant portion offunding has been dedicated tograduate student and post-doctoral education, throughindividual grants to principalinvestigators and the visitor’sprogram. The quality ofstudents and post-docs hasgenerally been high. And theCenter is now developingeffective programs to reach outto secondary school teachersand students. One examplecited by the Site Visit Commit-tee is a new program in

curriculum enhancement withthe Palos Verdes School District.

The site visit presentationscovered a wide range ofsubjects. Partnership opportu-nities were discussed by JimDavis (CDMG) in the areas ofprobabilistic seismic hazardanalysis fault parameters anddatabases, ground motionrecording and archiving, andoutreach and communication.Jim Mori (USGS) describedcooperative projects includingthe Los Angeles Region SeismicExperiment (LARSE), “PuttingDown Roots in EarthquakeCountry,” the Southern Califor-nia Integrated GPS Network(SCIGN), and an earthquake

response plan. Mori citedSCEC’s leadership roles inthe Earthquake Program inthe areas of education andoutreach (workshops,curriculum development),and infrastructure (the datacenter, portable seismicinstrumentation, andscientific seminars andworkshops).

The Science Director’soverview (David Jackson)consisted of a discussion ofSCEC’s basic scientificapproach to, and develop-

Posters were presented by SCEC summer interns at theNSF/USGS Site Review. Clockwise, from top: Post-docNed Field and Warren Washington (National Center forAtmospheric Research, Boulder, CO); NSF's SonjaSperlich with Kathleen Hodgkinson (USGS, Menlo Park);Mandy Johnson and Zheng-kang Shen; and Tom Henyeywith Maggie Glasscoe(USC) and Julie Pappas (USC).


Report continued from Page 4 ...

ment and implementation of,the master model. He de-scribed how the Center “gangtackles” such mega-projects asPhase II, LARSE, and SCIGN.Jackson also identified some ofthe important scientificquestions to be addressed overthe next few years.

Other presentations included“Future Earthquakes, Where

and How Big?” by Kerry Sieh(Caltech); “What HappensDuring an Earthquake Rup-ture?” by Steven Day (SanDiego State University);“Focusing and De-Focusing,How Do Seismic WavesInterfere?” by Paul Davis (UCLos Angeles); “EngineeringImplications, What Happens atthe Site?” by Ralph Archuleta(UC Santa Barbara); “Engineer-

ing Applications, CUREe, C-Cubed” by Geoff Martin(University of SouthernCalifornia); “Post-EarthquakeStudies, What Have WeLearned?” by Egill Hauksson(Caltech); and “SouthernCalifornia Integrated GPSNetwork and GPS Results” byKen Hudnut (USGS).

A series of status reports were

also presented on the SouthernCalifornia Seismic Network(Hauksson), the SCEC DataCenters (Rob Clayton, Caltech),the SCEC Education Program(Curt Abdouch), KnowledgeTransfer Program (JillAndrews), and Managementand Leadership (Tom Henyey).♦

The Site Visit Committee summarized the strengthsand weaknesses of SCEC with the followingrecommendations:

•The Site Visit Committee enthusiasticallyendorses SCEC’s proposed science plan defining itsmission for the next five years.

•The Site Visit Committee encourages SCECto seek greater participation by women scientists inSCEC management, and to increase participation ofunder-represented minorities at all levels, withparticular emphasis on SCEC education andoutreach activities.

•The Site Visit Committee encourages SCECmanagement to continue its efforts at diversifyingits sources of support for Center activities over andabove NSF STC support.

•The Site Visit Committee recommends thatSCEC management make a concerted effort to obtain

substantial funding from the State of California.

•The Site Visit Committee encourages SCECmanagement to carefully reexamine scientificpriorities in light of changes in funding for a specialproject to minimize detrimental effects on thegeneral scientific/infrastructure budget.

•The Site Visit Committee agrees with theExternal Advisory Council that the Center develop astrategic plan.

•The Site Visit Committee congratulatesretired Scientific Director Aki for his vision andservice in helping to build SCEC, and has fullconfidence in new Center Director Henyey andScientific Director Jackson for guiding SCECthrough the next five years.

•The Site Visit Committee recommends thatthe Center be funded as requested.

Review Team's Recommendations

Jill Andrews and Tom Henyey



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Southern California Earthquake Center Knowledge Transfer Program

The SCEC administration actively encourages collaboration amongscientists, government officials, and industry. Users of SCEC scientificproducts (reports, newsletters, education curricula, databases, maps, etc.)include disaster preparedness officials, practicing design professionals,policy makers, southern California business communities and industries,local, state and federal government agencies, the media, and the generalpublic.

Knowledge transfer activities consist of end user forums and workshops,discussions among groups of end users and center scientists, writtendocumentation and publication of such interactions, and coordination ofthe development of end user-compatible products.

Planned and In-Progress Products and Projects include:

• Insurance Industry Workshops; Proceedings; Audio tapes• Engineering Geologists' Workshops; Proceedings; Geotechnical

Catalog.

• Vulnerability Workshops, City and County Officials• Media Workshops• Field Trips• Quarterly newsletter• "Putting Down Roots in Earthquake Country" Handbook• WWW SCEC Home Page (http://www.usc.edu/go/scec)• SCEC-Sponsored Publications; Scientific Reports

For more information on theKnowledge Transfer Program, contactJill Andrews, phone 213/740-3459 oremail [email protected], orMark Benthien, 213/740-1560; [email protected].

Excerpts

“...for me, this visit marks the beginning of what I hope will be␣ anon-going dialogue with you....␣ ␣

“I must confess that I considered today’s meeting such animportant␣ event that I wrote an editorial for the magazine,American␣ Scientist, that I entitled The Arlington Rotary Club.␣ ␣

“The title, The Arlington Rotary Club, attractedconsiderable␣ attention, as I had hoped, in a magazine which hasprobably never␣ published those three words before, in anycombination. Few things␣ strike more fear into the hearts ofscientists—who are otherwise␣ supremely confident—than theprospect of speaking to an audience␣ of many non-scientists. Andso the article seemed to get a pretty␣ careful reading.␣ ␣

“Scientists, as you probably already know, like to talk toeach␣ other. We have our conferences, workshops, and seminarswhere we␣ converse in a jargon that can sound like its own form of

NSF Director Lane Encourages Scientists

to Reach Out to the Public

In late August, NSF Director Neal Lane, who has called on␣ scientists to becomemore active in communicating with the public,␣ addressed the Arlington, VA RotaryClub. We feature excerpts from an article that appeared in The Washington Postfollowing Lane’s speech. —SQN Ed.

Close␣ Encounters Of The Third Kind.␣

“I am a physicist and I have been told that physicists are a bit␣ odd.About a year ago the wonderfully witty journalist withThe␣ Washington Post, Joel Achenbach, wrote a tongue-in-cheek␣ description of a physics conference. He said, ‘When youpicture a␣ physicist you should imagine a person in darkness,holding a␣ remote-control device, lecturing,...’ Frankly, I don’t seewhat is␣ so strange about that! It’s how I grew up! I hope I canoffer␣ some thoughts today with the lights on and the languageaccessible.␣ ␣

“In my editorial in the American Scientist, I spoke ofthe␣ importance of scientists getting out of their labs, offtheir␣ campuses, away from their computers, and into a dialoguewith the␣ American public. I used myself as an example ofsomeone who lacks␣ frequent experience in talking about scienceto audiences that are␣ not scientists or specialists in science policy.␣ ␣

See "Lane" on Page 7


Lane continued from Page 6 ...

“...In a sense, NSF gives grants to people who pose probingand␣ insightful questions and then relentlessly test the answerstill␣ they create new kernels of knowledge and understanding.These␣ kernels are like pebbles tossed into a pool of water.They␣ generate an ever expanding series of circles—circles ofopen␣ knowledge for others to contemplate, add to, and combinefor␣ amazingly varied and practical uses.␣ ␣

“The Nobel prize-winning physicist, Charles Townes, provedthe␣ concept behind the laser in the 1950s. [He was not supportedby␣ NSF but by our Wilson Blvd. neighbor, the Office of NavalResearch (ONR).]␣ This discovery was the pebble that eventually

"...everyone, scientists included,should be able to explain␣ what theydo and make it sound sensible orrelevant."

led to commercial lasers that␣ read␣ compact disks, perform eyesurgery and burn away blood clots, and␣ pulse phone calls andcomputer data through thousands of miles of optical fiber. It isspeculated that there are many more circles␣ to come from this onepebble. And so you might say that we and our␣ fellow scienceagencies are in the business of funding ‘pebble␣ shooters.’␣ ␣

“At NSF, all of our surveys show that the public is interested inscience,␣ and believe science is important but nonetheless thosesurveyed also␣ believe they have very limited scientific under-standing. When I mention␣ this to scientific audiences I suggest tothem that the survey results␣ perhaps tell us more about␣ thescience community than about the American public. Ihave␣ pointed out that this disconnect between the publicbeing␣ interested in science yet feeling that their knowledge isvery␣ limited should give all of us something to ponder.␣ ␣

“There is no doubt that scientists are intense about whatthey’re␣ doing and the minutia of their particular discipline or subfield.␣ And yet everyone, scientists included, should be able toexplain␣ what they do and make it sound sensible or relevant. If Iwere a␣ surgeon, or a plumber, or a journalist, or even a musician, Icould␣ report on the kind of surgeries, leaky faucets, news stories,or␣ compositions I had worked on. When you’re a scientist, thethings␣ that you do on any given day in the laboratory are not

"...our surveys show that the public isinterested in science,␣ ... but nonethelessthose surveyed also␣ believe they havevery limited scientific understanding....this disconnect between the publicbeing␣ interested in science yet feelingthat their knowledge is very␣ limitedshould give all of us something toponder.␣ "

very␣ interesting even to your spouse, although you find themcompletely␣ absorbing. I know this from personal experience.␣ ␣

“And so there is this odd contradiction because almost allpeople␣ are interested in how things happen or why they happenor how they␣ work, but there is a narrow and minute level of detailthat most␣ scientists work at that can quickly baffle or bore evenother␣ scientists. A partial solution to this disconnect is toeducate␣ scientists on how to be better communicators not onlyabout their␣ particular work but about the role and value of scienceand␣ technology to society. Some scientists are skilled␣ communi-cators—Carl Sagan, Stephen Gould—but the number is small.␣ ␣

“While on the one hand, science seems very remote to mostpeople,␣ it is, on the other hand, completely pervasive in our lives.The␣ world is so infused with the stuff of science that we oftendon’t␣ recognize how it permeates every detail of our dailyroutine....␣ [At this point, Lane cited various uses of technology.]␣ ␣

“So, why do I think it is important for scientists to get out of␣ theirlabs and engage in a genuine dialogue in their communities?␣ It isnot because I think that they have the only important things␣ tosay, but rather that they need to hear what everyone else hasto␣ say, as well as offer their own information and opinions.Will␣ this make them better scientists? Probably. I havefrequently␣ pointed out that in America we are able to do out-

standing science␣ at the same time that many societal disparitiesand problems are␣ increasing. Maybe the most important goalshould be to understand␣ the physical, moral, and social problemsthat hold us in the grip␣ of numerous contradictions. Surely wecan only do this together,␣ through regular and open discussions.␣ ␣

“Now, am I suggesting by my comments that science is notimportant␣ or inherently useful? Just the opposite. The contribu-tions of␣ science and technology to our society translate into higheconomic␣ and social value. Economists of all political stripeshave␣ estimated that our national investments in support ofscience and␣ technology activities yield rates of return in the range

See "Lane" on Page 10



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SCEC Research ReportSCEC Research ReportSCEC Research ReportSCEC Research ReportSCEC Research Report

n early August of this year, aresearch team from theUniversity of SouthernCalifornia (USC) collaboratedwith researchers from the USGeological Survey (USGS),Incorporated Research Insti-tutes for Seismology (IRIS),and the University of Califor-nia at Santa Barbara (UCSB) tocarry out an experiment in theLanders area of the MojaveDesert. The purpose of theproject was to record explo-sion-excited seismic guidedwaves trapped in the fault zonethat ruptured in the M7.4earthquake of 1992.

This experiment, supported bythe National Science Founda-tion (NSF) and the SouthernCalifornia Earthquake Center(SCEC), is a duplicate of theprevious experiment con-ducted in 1994: to monitor anypossible changes in faultgeometry (the width, depthand shape) and physicalproperties (velocity, porosityand material quality) after theLanders earthquake, usingfault-zone trapped waves.

Principal Investigators Yong-Gang Li and Kei Aki, withother scientists, have publisheda series of papers on fault-zoneguided waves (in Science,Journal of Geophysical Research,and the Bulletin of the Seismo-logical Society of America). Thepapers show that fault-zoneguided waves can be used toprobe the state of the faultzone, because these guidedmodes are formed by multiple

Monitoring the Post-Seismic Changes of the Landers

Fault Using Fault Zone Trapped Waves

reflections within the faultzone, and their featuresstrongly depend on thegeometry and physicalproperties of the fault. The PIsand their colleagues havesuccessfully observed thesedistinct waves from earth-quakes at many active faults inCalifornia, including the SanAndreas fault at Parkfield, theSan Jacinto fault near Anza andthe fault at Landers. Theseexperiments should advanceour understanding of the staticand dynamic mechanismsassociated with earthquakeoccurrence on these faults.

In the present experiment,

three 4-10 km-long lineararrays consisting of 68PASSCAL portable instrumentswere deployed across andalong the fault trace betweenYucca Valley and HomesteadValley. Three explosions using500-1200 pounds of chemicalemulsions were detonatedwithin the fault zone atdistances of 2 km, 5 km and 15km from the mainshockepicenter of 1992. The 68recorders worked in a continu-ous recording mode not onlyfor the explosions but also foraftershocks (there are still morethan ten microearthquakesoccurring there per day). ThePASSCAL instruments and the

team members all sufferedthrough the intense desert heat,with temperatures soaring ashigh as 120 oF.

A unique data set was collectedfrom both the explosions andthe aftershocks, including a M4.5 event on August 14. Thesedata will be used for a com-parison with those recorded inthe 1992 and 1994 experimentsto search for any changes infeatures of fault-zone trappedmodes. The results will bereported at the Fall meeting ofthe American GeophysicalUnion. ♦

Y. G. Li

L-R: David Bowman, David Adams, Yong Gang Li, Joel Wedberg (all USC), and Arturo Suria (IRIS). YongGang Li identifies the instrument deployment locations around the Landers fault zones.

I


Clockwise, from top left:

1. The IRIS consortium instruments used for seismic data acquisition,including a personal computer, REFTEK data recorder, and GPSsatellite antennae and receiver.

2. Three component geophones, such as this one, picked up signalsfrom the Landers seismogenic zone.

3. This concrete foundation was separated and offset during therupture of the 1992 M 7.5 Landers earthquake.

4. Batteries will keep individual stations running for a week.

1 2

3

4



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Lane continued from Page 7 ...

of 20-30 percent. I wish I could find a broker who would promisea similar␣ return, an honest one.␣ ␣

“One need look no further than the streets of Arlington tofind␣ high-tech industry. There are major players like MCI andAmerican␣ Management Systems. Just as important, however, isscience and␣ technology as a driver of small business development.I know I can␣ rely on you to provide me with the best examplesfrom your own␣ experience.␣ ␣

“Suffice it to say that all these returns flow back to our society innew industries, high-value jobs, and highly competitiveproducts␣ and services for the domestic and global marketplace.They bring␣ us better health care, a cleaner environment, and animproved␣ standard of living. Despite this, science by itself cannotanswer␣ the hardest questions.␣ ␣

“The most fundamental problems in all societies are humanproblems␣ and they are similar on the local and global scale. Howcan we␣ nurture and educate all children, inhibit violence,provide␣ meaningful work for all? Science can help solve theseand myriad␣ others that exist. But science is only one of numerouscomponents␣ that are needed.␣ ␣

“I am asking scientists and engineers to actively reach out in␣ theircommunities and engage in a genuine dialogue. I am asking␣ youto reach out to scientists, and technical professionals as you␣ havedone to me, and share with them the problems and issuesof␣ concern in this community. Rotarians, especially, have the giftof␣ reaching out. Together, we can keep talking and movingtoward␣ beneficial solutions.” ♦

To SCEC Scientists and Friends,

I hope everyone had a wonderful summer. I would like to bringyou up to date on several items.

1. The eight-month process to prepare, submit, and defend theSCEC Five-Year (1997-2002) renewal proposal is now over. TheSteering Committee began work on the renewal in January witha day-long session where committee members presented theirideas on the future direction of SCEC.␣ During the spring, severaldrafts were written and circulated among the␣ committee. Thefinal proposal emphasis was approved by the board inearly␣ June and the proposal was completed and submitted toNSF in late June.

The␣ science proposal was primarily written by David Jackson,Science Director, and Tom Henyey, Center Director, with RalphArchuleta, Egill Hauksson, and Kerry Sieh. Jill Andrews andCurt Abdouch prepared the education and outreach section.The process was completed when review teams from NSF andUSGS visited USC in late August (see Review Report, page 3 ofthis SQN). At this review, members of the Steering␣ Committee(with help from Paul Davis and Norm Abrahamson)made␣ presentations on the current status of SCEC and the newresearch thrusts presented in the proposal. Several round tablediscussion sessions also took place with Steering Committeemembers. Approximately 20 post-docs,␣ graduate and under-graduate students prepared posters and had a discussionsession with the site team.

Based on the written reviews of the proposal (all checked excellent)and the favorable comments made at the site visit, we feel confidentthat SCEC will continue to be funded for the next five years.

2. We received written confirmation of NSF approval of the␣ newSCEC directors. Tom and Dave are now officially in charge.

3. There are several changes to the Board and Steering␣ Committee.Charles Sammis has replaced Kei Aki as the USC member onthe␣ Board. In honor of his service to SCEC, Kei Aki has been giventhe status of Director Emeritus and made an ex-officio member ofthe Steering Committee. Dave Jackson has replaced Aki as leader ofthe Master Model Working␣ Group and Ken Hudnut has replacedDuncan Agnew (on sabbatical in New␣ Zealand) as leader of theCrustal Deformation Working Group. Jim Davis (CDMG) and WillPrescott (SCIGN Coordinating Board Chairman) have been electedas ex-officio members of the Steering Committee.

4. The SCIGN program is moving ahead. SCEC recently receiveda␣ $2M grant from NSF (through the ARI program) to expand thepermanent GPS␣ array in southern California. More on␣ this activitywill be presented at the annual meeting in late October.␣ ␣

Open Letter from John McRaney, SCEC Director for Administration


SCEC Scientists' PublicationsSCEC Scientists' PublicationsSCEC Scientists' PublicationsSCEC Scientists' PublicationsSCEC Scientists' Publications

The Geology of Earthquakes by R.S. Yeats, K.E. Sieh, andC.R. Allen: Oxford University Press, 576 pages

This is the first modern textbook on earthquake geology whichdraws examples from many seismically active regions of theglobe, including China, Japan, the Mediterranean countries, NewZealand, and the United States. The authors have written thebook as a valuable reference for the community of practicingengineers, geophysicists and planners as well as geologists; and asa textbook for graduate and advanced undergraduate students.For readers with little or no geological or geophysical back-ground, the first seven chapters provide information on platetectonics, structural geology, earthquake waves, geodesy, timescales and dating techniques, and tectonic geomorphology. Theseare followed by a discussion of earthquake environments: strikeslip, reverse, normal, and subduction zones, plus a chapter onsecondary effects such as liquefaction, seismically inducedlandslides and tsunamis. Case studies throughout the text ofrecent, well-studied earthquakes demonstrate the interdiscipli-nary nature of earthquake science. The final chapter details thelatest methods and breakthroughs for seismic hazard assessment.All chapters contain the most recent studies, referenced in both“Suggestions for Further Reading” at the end of each chapter aswell as an extensive 50-page bibliography.

The authors’ intent for the book to be used as a reference isevident in the exhaustive appendix, which includes a table ofmore than 300 historical earthquakes with surface rupture, a

The Geology of Earthquakes Now Available

complete glossary, bibliography, and a comprehensive index ofboth terms and names. Finally, throughout the book are personalvignettes of early pioneers including Gilbert, McKay, Koto,Darwin, and others.

The Authors

Robert S. Yeats is Professor of Geology and Oceanography atOregon State University and is chairman of the Task Group inPaleoseismology, Inter-Union Commission on the Lithosphere.

Kerry E. Sieh is Professor of Geology at the SeismologicalLaboratory of the California Institute of Technology, a member ofthe National Academy of Sciences Committee on the Science ofEarthquakes, and a recipient of the National Academy of SciencesAward for Initiatives in Research.

Clarence R. Allen is Professor Emeritus of Geology and Geophys-ics at the California Institute of Technology, a past-president ofboth the Geological Society of America and Seismological Societyof America, and a member of the National Academy of Sciencesand the National Academy of Engineering. He is also the 1996recipient of the Medal of the Seismological Society of America.

The Geology of Earthquakes is available direct from the publisher at800-451-7556, by company purchase order or credit card (Visa,Mastercard and American Express). It may also be orderedthrough major bookstores. ♦

Mark Benthien

SCEC Quarterly Newsletter Now Highlights Recent Publications

Beginning with the current issue, SQN will highlight recent publications of SCEC scientists in an expanded format and also provide more in-depth information such as abstracts or interviews with authors. We will continue to provide a complete bibliographical listing of SCEC researchpublications in the Spring issue each year. The most recent publications by SCEC researchers are listed on page 21.

We plan to expand our database of publications of research funded by SCEC to include abstracts. We are asking all SCEC-funded researcherswho wish to have their publications included in the database, to email or fax Mark Benthien, SCEC Outreach Specialist (contact informationbelow), with information on the authors, title, publication name and any other bibliographic information that is known. We are asking that thisbe done before submitting a paper, in order to facilitate assignment of the “SCEC contribution number” for the acknowledgment section. This willgreatly improve the function of the SCEC database, allowing for key word searches in both the title and abstract of all papers. This database willsoon be available on the Internet at SCEC’s home page: www.usc.edu/go/scec.

For each issue of the SCEC Quarterly Newsletter, selected abstracts will be taken from the database and printed, with further information orinterviews with selected authors.

Please support both new projects by emailing or faxing both past (if readily available) and future abstracts of your SCEC-funded publications.

Mark Benthien, Outreach Specialist email: [email protected] California Earthquake Center tel (213)-740-1560USC, University Park Campus fax (213)-740-0011Los Angeles, CA 90089-0742



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Quarter FaultQuarter FaultQuarter FaultQuarter FaultQuarter Fault

The San Cayetano Fault

Length: 40 kmSlip Rate: 4 -11.8 mm/yrCumulative Offset: 10.1-11.8 kmMaximum Magnitude: 7.2Recurrence Interval: 500 years

Each Issue of the SCEC Newsletter features asouthern California fault. In this issue...

See "San Cayetano" on Page 13

Interview with Bob Yeats

SCEC: James Dolan (University of Southern California) hasestimated that the San Cayetano fault could produce a M 7.2event every 500 years. What effect, in your opinion, would thishave on Los Angeles?

Yeats: A M 7.2 earthquake could produce some damage in LosAngeles. This is due to an effect that was demonstrated in 3-Dbasin modeling by Kim Olsen, Ralph Archuleta, and Joe Matarese(of UC Santa Barbara, in the Bulletin of the Seismological Society ofAmerica, 86, 575-596, 1996). An increase in amplitude and adecrease in the speed of surface waves occurred in the model. Idon’t know if the damage would be major, however. Olsen et al.modeled an earthquake occurring on the San Andreas fault as thesource, but such modeling has not yet been done to predict theeffects of a M 7+ event in the Ventura basin.

SCEC: Has the San Cayetano fault produced a significant earth-quake in the last 500 years?

Yeats: We do not know. This is one of the purposes of thetrenches Dolan and Rockwell are excavating on the San Cayetano.The problem is that there are very few suitable trench sites, but

The San Cayetano, a 40 kilometers-long,north-dipping reverse fault, bounds the SantaClara Valley on the south. Located west ofthe Santa Susana fault, the San Cayetano mayhave a slip rate of over 10 millimeters peryear. This could make it the fastest slippingthrust fault in the Transverse Ranges.

For this newsletter, Bob Yeats, Professor of Geology and Oceanography at Oregon State University, was kind enoughto discuss the San Cayetano with the writer. Yeats, who has co-authored a new geology textbook with Kerry Sieh and

Clarence Allen (both of Caltech), has supervised several 3-D studies of the fault using oil field data. (See the SCECreview of The Geology of Earthquakes, page 11 of this newsletter.)

they have selected some that have promise.

SCEC: What is the slip rate and the range of offsets for the SanCayetano that you and Gary Huftile (Oregon State University)have produced?

Yeats: We’ve summarized that information in Huftile and Yeats,the Bulletin of the Seismological Society of America, 86, 1B, s3-s18(1996) Northridge special issue. The information in that paperpostdates SCEC’s Phase II report but will be incorporated intoPhase III, due for release in early 1997. We calculate 2.2-5.2 km dipslip in the last 500 ky and 10.1-11.8 km of dip slip in the last 975+/175 ky for the Modelo lobe. The Modelo lobe is the easternlobe of the fault where the displacements are largest. This givesus a slip rate of 4.4-10.4 mm/yr for the last 500 ky and 10-11.8mm/yr for the last 975 ky (see table 1 of Huftile and Yeats, 1996).The western San Cayetano fault has lower slip rates decreasing tozero in the Ojai Valley, but this is because part of the fault is ablind thrust uplifting Sulphur Mountain. (For reference, see theeastern cross section in Huftile and Yeats, Journal of GeophysicalResearch, 100, 2043-67,1995).


See "San Cayetano" on Page 14

San Cayetano continued from Page 12 ...

SCEC: Was the San Cayetano originally a normal fault which wasreactivated as a strike slip fault?

Yeats: Possibly. In Yeats et al., American Association of PetroleumGeologists 78,1040-1074 (1994), we map a SE trending trough,dated in the late Miocene, from the outcrop in the condor refugenorth of Fillmore to the subsurface NE of the Santa SusanaMountains. The SW edge of this Miocene trough could be the siteof the Pleistocene San Cayetano fault, but because the oldestsediments in the footwall of the San Cayetano are upper Pliocene,we can’t demonstrate that. If so, then the San Cayetano reacti-vated an old normal fault, as did the Santa Susana fault fartherSE, as discussed by Yeats et al. (1994).

SCEC: Where is the best place to view the fault?

Yeats: Silverthread oil field in the upper Ojai Valley. Rockwelland Huftile led the SCEC field trip there last fall. (See cover photo––SQN Ed.) ♦

Above: Map showing the location of the San Cayetano fault, with relation to theSanta Susana (SSF), Oak Ridge, Santa Monica Mountains and Santa Monicafaults. The barbs point down dip on the faults. Dark spots indicate the geometryof recent ruptures. The likely maximum magnitude event and its recurrenceinterval is indicated for each fault. (Figure modified from Dolan et. al, Science,267, 199-205, 1995)

The chaparral covered Eocene rocks along the skyline form the hanging wall of the SanCayetano fault in the Orcutt Canyon area, where Eocene rocks are thrust 7 to 8 km(stratigraphic separation) over overturned mid-Quaternary marine deposits of the Fernandoformation. View is to the north.

San Cayetano fault in the upper Ojai Valley looking east. Sisar Canyon fan isin the foreground and the San Cayetano is expressed as a prominent scarp,vertically displacing the fan by nearly 100 m. In the distance, the SanCayetano brings overturned Eocene rocks on the north (left), over overturnedQuaternary deposits of the Fernando formation to the right.

Courtesy Tom Rockwell

Courtesy Tom Rockwell



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San Cayetano continued from Page 13 ...

Contact the SCEC Knowledge Transfer Office, phone 213/740-1560or fax 213/740-0011

e-mail [email protected] information on how to reserve a space!

Save the Date!Save the Date!Save the Date!Save the Date!Save the Date!

Join us for the

Southern San Andreas Fault

Field TripFriday and Saturday, December 6 and 7, 1996

with Dr. Kerry Sieh

SCEC: Why does the San Cayetano fault have two lobes?

Rockwell: There’s a lateral ramp between the two, which runsalong the east side of Sespe Creek and separates the SanCayetano into two lobate segments. The eastern segment ismuch more lobate than the western and has a lower dip in theupper several kilometers.

SCEC: Is the primary purpose for the trenches you’re doingwith Dolan to look at the fault’s slip rate?

Rockwell: The intent of the trenching is to resolve the timingof the most recent earthquakes, and, if possible, the amount ofslip in those earthquakes. We suspect that whatever slipvalues we come up with for the western segment, they will be

minimums, considering the extensive late Quaternary defor-mation of the footwall indicating a blind component of slip.

Ralph Archuleta, on strong ground motion during a hypo-thetical M 7.2 earthquake:

For a San Cayetano rupture, the directivity effect would be feltstrongly in the direction of Los Angeles, because the rupturewould proceed updip going from north to south. That wouldcertainly be different from the 1994 Northridge earthquake,when the rupture went basically southwest to northeast. AsYeats may have mentioned, the Ventura basin has as deep asection of sediments as Los Angeles (The Oxnard plain). AM 7.2 event on the San Cayetano could produce some verysignificant amplification and basin edge effects here. ♦

Michael Forrest

More Observations on the San Cayetano fromSCEC Scientists Tom Rockwell and Ralph Archuleta

The San Cayetano fault and the Oak Ridge fault are the focus of a SCEC field trip to be scheduled in1997 and led by San Diego State University professor and SCEC scientist Tom Rockwell. Rockwell, whothis year has trenched sites in Israel, Turkey and Mongolia, was available for comment, as was UC SantaBarbara seismologist and SCEC Board member Ralph Archuleta. Rockwell did part of his Ph.D. thesiswork on the San Cayetano, and authored one of the seminal papers on the fault (Geological Society ofAmerica Bulletin, 100, 500-513, 1988).


Feature: visit with a SCEC scientist

Mark Legg

See "Legg" on Page 16

Profi leProfi le

The Interview

ark Legg's field area is the Southern Califor-nia Borderland. While some scientists discountthe possibility of destructive tsunamis occurringalong coastal Los Angeles, Orange and SanDiego counties, Legg believes they are inevitable.

Legg, unlike many of his colleagues, is alsoconvinced that current published probabilisticseismic hazard estimates for the coastal regionare “too low.” “Nobody really knows the sliprates on these offshore faults, except for thosewhich are known to pass onshore,” says Legg.“Without accurate accounting of the offshoreearthquake threat, estimates of seismic hazardsin the coastal zone, as currently presented,underestimate the risk. The Borderland areacovers approximately one third of the southernCalifornia area, yet has half of the faults—andwe don’t have numbers for them,” observesLegg.

Mark Legg received a B.S. in Space Science andMechanical Engineering magna cum laude fromthe Florida Institute of Technology in 1973. HisM.S. in Oceanography is from Scripps Institutionof Oceanography (1980) and his Ph.D. in Geo-logical Sciences is from U.C. Santa Barbara(1985).

He is a Senior Scientist at Torrance-based ACTAInc. since 1989. ACTA Inc. specializes in riskassessment for both natural and man-madehazards. He is also an Adjunct Professor at SanDiego State University and a Visiting AssistantResearch Geophysicist at the Institute for CrustalStudies at UC Santa Barbara. Legg and his wifeJoyce have two sons, Geoff (11) and Justin(almost 8).

M

SCEC: The largest recent earthquake that occurred just off ourcoast was the M 5.8 Oceanside earthquake in 1986. What can youtell us about it?

Legg: The earthquake occurred on the restraining bend of anunknown thrust fault that is clearly constrained by the right-lateral San Diego fault block zone. On a 1990 USGS cruise I wason with Dr. Robert Bohannon and Dr. Steve Eittreim of USGSMenlo Park (they were co-chief scientists for the May 1990 MCScruise in the Borderland), we sailed over the epicenter of thatearthquake and found that the San Diego Trough fault is essen-tially near vertical there. My best guess is that the Oceansideearthquake was on the Thirtymile Bank detachment fault, whichis offset by the younger San Diego Trough fault. There is a bumpon the seafloor there and all the aftershocks span the width of thatbump. They extend all the way from the San Diego trough faultto the Coronado Bank fault zone.

SCEC: What is the maximum earthquake which could be gener-ated by that fault?

Legg: The San Diego Trough fault could generate a M 7.5. Basedon my thesis data at Scripps and Santa Barbara, it’s a 50 to 200km-long fault. But it’s not the biggest fault we have to beconcerned with out there. The biggest fault is the San Clemente,which has a length of at least 400 or 500 km and may extend as farsouth as Viscaino Bay.



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Legg continued from Page 15 ...


"Mark Legg is full of energy. He produces creative ideas thatstimulate new directions for discussion."

Tom RockwellProfessor of Geology and SCEC Scientist

San Diego State University

SCEC: Is there any evidencethat the San Clemente fault hasruptured in its entirety?

Legg: I don’t know how we’dever prove that. Certainly it’shard enough to prove on land.Look, for example, at the SanAndreas fault. It has beensuggested that the north andcentral Carrizzo Plain segmentruptured with the CoachellaValley segment, but even withthe best land data, we just can’tprove it.

What we can show is thatfaults like the San Clementefault are very long, verycontinuous, narrow, well-defined faults. Their characteris very much like the characterof the San Andreas fault. Wehave the same sort of geomor-phology, we have majorrestraining bends with seaflooruplift, we have extensionaltrans-tensional segments withsagging of the sediments intothe extended fault zone, andthese features are all consis-tently developed where thefault wiggles left into restrain-ing bends, and right intoreleasing zones.

SCEC: Do you believe that the

San Clemente fault may be asimportant a fault as thesouthern San Andreas in thetectonic evolution of southernCalifornia?

Legg: Yes, the San Clementefault is very much like the SanAndreas fault in character: verylong, continuous, and verywell defined. If we assume theSan Clemente fault is the SanAndreas of the offshore, it wasmost likely the main plateboundary fault prior to fivemillion years ago for as long as20 to five million years ago —three times as long as the SanAndreas in southern Califor-nia. Prior to five million yearsago, the “offshore SanAndreas” therefore jogged tothe right which resulted in therotation of the TransverseRanges.

But activity on the SanClemente fault didn’t stopwhen the plate boundaryjumped into the Gulf ofCalifornia at five million years.The fault is still active. I thinkbased on its length and itswell-defined character, that itcould produce M 8 earth-quakes. How frequently, Idon’t know.

SCEC: How far south does thefault extend?

Legg: It probably connects tothe San Ysidro fault in Baja atits southern terminus. Theimportant thing to rememberis that the San Clemente fault,to our knowledge, does notcross Baja anywhere. So all theslip and seismicity on spread-ing centers in the mouth of theGulf of California do notaccount for motion on the SanClemente fault. I believecurrent plate motion modelsare at least ten percent if not 20percent slow, and that the SanClemente fault has perhaps tenpercent of the Pacific-NorthAmerican plate motion, aboutfive mm per year. I base thisestimate on geomorphicfeatures which I see on theFortymile Bank (40 miles westof San Diego). There are whatI believe to be debris flowsfrom a submarine fan slopeapron debris flow complexthat are progressively offset. Iestimate they are a quarter ofmillion years old. The largerfeatures are offset ten km.There is a shudder ridge therewhich is controlling thesedimentation. We haven’tdone the detailed sampling

necessary to prove the age ofthese deposits or to provewhere they are derived from,but my estimate is based onmorphology and high resolu-tion seismic profiling.

SCEC: Is there any historicalrecord of a large tsunamioccurring in southern Califor-nia?

Legg: I’ve talked to a NOAAinvestigator, who believes thatthe only major local tsunami insouthern California on recordoccurred during the M 5.25earthquake on August 30, 1930in Santa Monica Bay. It was 20feet high and caused onefatality. Santa Monica is semi-enclosed which produces localbay resonance. In the M 9.2Alaskan (Prince WilliamSound) earthquake on March23, 1964, the effects of thetsunami lasted for17 hours inSanta Monica Bay because ofthis resonance effect. Itexceeded the tide gauge high(more than nine feet high atMarina del Rey), because that’sthe location of the antinode —the peak response site — forthe Santa Monica Bay. The


Legg continued from Page 16...


water went up and down ninefeet every 20 to 30 minutes. Itdestroyed a lot of watercraft.The same thing also happenedin 1960 in the San Diego bayafter the M 9.5 Chileanearthquake on May 22, 1960.

SCEC: Which offshore faultscould potentially producetsunamis in southern Califor-nia?

Legg: All the major offshorefault zones: the San Clemente(the biggest), the San DiegoTrough, Coronado Bank/PalosVerdes, the Rose Canyon/Newport-Inglewood, theCatalina, the San PedroChannel, the faults in SantaMonica Bay, Anacapa-Dume,Santa Barbara Channel, theOak Ridge fault, the Pitas Pointfault, the Red Mountain fault,the North Slope fault zone. Allthese major offshore faults areactive. The ones closer to theTransverse Ranges are thrust,so they have the greatestpossibility of generatingseafloor deformation and largetsunamis. But even the strike-slip faults have major restrain-ing bends and releasing bendswith possible seafloor uplift orsubsidence.

I think you could haveearthquakes big enough totrigger landslides ten tohundreds of km long, withthese old detachment faults,and especially with slowearthquakes. The Newport-Inglewood fault, for example,has been reactivated as a strike-slip fault which runs throughslippery rock, like the Catalinaschist.

SCEC: Let’s specifically

consider the flatter beaches inL.A. or Orange County.

Legg: If we have a largeearthquake, we may not have atsunami. But if a tsunami isgenerated, the size of thetsunami at the source isgenerally comparable to theamount of seafloor deforma-tion. If it’s in deep water, thewave will be amplified when itgets to shallow water. Theenergy is spread through theentire water column, whereasthe regular surf, the swellwhere the surfers ride, is onlyin the upper tens of meters ofthe ocean. So a large earth-quake in 1000 to 2000 meterswater depth, with a two-meterwave, may amplify to perhapsfive to ten meters by the time itgets to the coast, depending on

coastal geometry, refractionpatterns, and so forth.

SCEC: So if you’re sitting withyour toes buried in the sand inHuntington Beach, you couldactually look up into the bluesky and see a 30-foot wavecome at you?

Legg: Absolutely. Localamplification can create suchwaves. And as we saw in theJuly 12, 1993 Hokkaido-Nasei-Oki earthquake (M 7.8), whichcaused a major tsunami atOkushiri Island, on the Sea ofJapan, the tsunami averagedabout five meters, in someplaces it was ten meters high,others only four meters high.But in one small narrowcanyon on the steep coast, itwent up 30 meters. They know

it reached the 100-foot eleva-tion in this canyon becausethere was seaweed draped overthe telephone lines.

SCEC: Have you seen any ofthe seafloor faults firsthand?

Legg: My only submersibletrip (to date) occurred inDecember of 1989 aboard theNavy DSV (Deep SubmergenceVessel) Turtle. It was along thesouthwest side of FortymileBank. There are spectacularescarpments there, most ofwhich are directly related totectonic faulting, but majorslope failures are also commonin the area. My dive was veryeducational for myself,especially in demonstratingthat large parts of the seafloorare covered with mud!

Toward the end of the dive, wereached the steeper scarps,where tidal or other bottomcurrent scour kept the bedrockclean of mud, and I saw largepiles of large boulders. Thesecond dive in this Woods HoleOceanographic Institute(WHOI)/Navy test cruiseinvolved a young Navy cadetand M.S. candidate from M.I.T.,Ms. Lynn Oschman. The divewas planned based on SeaBeam contour maps acquiredduring the previous night(after my dive) where weidentified a small bench in the500-m high scarp. From mydive, I had learned that thebottom currents in this area arequite strong and the bench waslikely the only good placewhere Turtle could hold stilllong enough to get a sample.

US Navy DSV Turtle. Legg is getting aboard(standing on top of vessel).



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Furthermore, I predicted thatthe bench was likely of tectonicorigins, and we should getsome fault rocks. Lastly, thesteep scarp should havespectacular exposures forphotography. When Turtlereturned from this dive, I waselated to see a large (briefcase+sized) chunk of rock which wascovered with slickensides,retrieved from this bench.Lynn also told me that thescarp was near vertical forhundreds of feet, leveled off toabout a 60-degree slope, flat forabout a100-m wide bench, thenbecame near vertical again. Ihave yet to see the video tapesor 35 mm slides from this dive(they are lost somewhere atWHOI), but I do have the rock,a fine museum specimen!

SCEC: What is the origin ofCatalina Island?

Legg: Catalina Island may be ahorst squeezed upwards due totranspressional motion on theCatalina fault (Catalinaescarpment) and the San PedroBasin fault zone. There aremany theories on the origin ofCatalina Island, but I know ofno consensus at this time.

An important question is whythere are no (or few) recogniz-able marine terraces onCatalina Island, whereas thereare abundant well-definedterraces on all the otherChannel Islands and PalosVerdes Peninsula. Perhaps theuplift has been very rapid, veryrecent, or the Catalina Schistand Miocene andesites whichmake up the bulk of the islandare not favorable for terraceformation/preservation. It is

likely that all of the ChannelIslands are the result offaulting, either directly withmajor fault scarps boundingone or more sides like SanClemente Island, or via majorlow angle normal, reactivatedas reverse faults like theNorthern Channel Islands.Certainly all of these islandsare fault-bounded blocks, andmost are tilted. Los Coronadosare beautiful examples of tiltedfault blocks with a general 25-35 degree west-dip, equivalentto the dip we imaged in theMCS profiles offshore SanDiego across Coronado Bank.Numerous submerged featureslike Coronado, Thirtymile andFortymile Banks were alsoislands during Pleistocenelowstands of sea level, andthey too are fault-bounded.

SCEC: Is there very muchhydrothermal activity occur-ring on our own Borderlandfaults?

Legg: There may be abundanthydrothermal activity on theseoffshore faults. Only thehydrothermal vents alongspreading centers, and recentlyalong the Florida escarpmenthave received much attention.Peter Lonsdale from ScrippsInstitution of Oceanographyfound hydrothermal ventsalong the San Clemente faultnear Fortymile Bank. Hydro-thermal vents are well-knownalong coastal faults, such asPunta Banda (the Agua Blancafault) and Carlsbad, wherethere was once a bath house.As seen on Life & Times, weobserved Dandelions on theCatalina escarpment, which arecreatures thought to be

associated with hydrothermalactivity. We did not recognizehydrothermal vents duringthose dives (saw no chimneys,black or white smokers, tubeworm colonies, giant clams, orother vent fauna). It is entirelypossible that such features existalong offshore faults, but verylittle of this enormous regionhas been surveyed by submers-ible or bottom photography.

SCEC: Are there any funda-mental differences in the wayoffshore vs. onshore faultsbehave?

Legg: Underwater faultsmisbehave. They don’t showthemselves topaleoseismologists for trench-ing, so it can be very difficult todetermine Quaternary earth-quake histories for such faults.On the other hand, highresolution seismic methods andcareful, well-navigated bottomsampling should allowaccurate determination ofQuaternary slip rates.

With regard to earthquakes onoffshore faults, we know thatlarge and small earthquakesoccur on offshore faults ofsouthern California: the largestseismographically recordedwas the 1927 Lompoc earth-quake (M 7.3).

Vertical stresses due to thewater column should be lessthan an equivalent layer ofgranite for an onshore fault,but more importantly, we wantto know, what is the influenceof water in the fault zone?

Most, if not all, onshore faultsextend below the water table,

and so many onshore faultsmay be “wet.” Rick Sibson(University of Otago, NewZealand) suggested thatpseudotachylytes are fossilearthquakes on “dry” faults(the water would inhibit themelt). But he also noted thatsomeone observed greatquantities of water emanatingfrom the overthrust granite ofthe White Wolf fault immedi-ately following the 1952 KernCounty (M 7.5) earthquake.Much debate and currentresearch is focused on theinfluence of water in faultzones; it may help account forthe “heat flow” deficit and lowapparent stress in largeearthquakes (pore pressurelowers the effective stress andwater may remove heat viahydrothermal activity so thatconductive heat flow measure-ments underestimate the heatgenerated along faults).

I think of more significance tooffshore (submarine) faulting,especially in the CaliforniaContinental Borderland, is theimportance of hydrousminerals and possible dehydra-tion/rehydration reactionsduring large earthquakes. Thisis because the Catalina Schistbasement is equivalent to someparts of the Franciscan base-ment elsewhere in California;and the San Andreas fault iscreeping where Franciscanbasement is juxtaposed versusthe granitic basement of Saliniaand the Transverse Ranges andPeninsular Ranges.



Wayne Thatcher and TomHanks (US Geological Survey)and others studied stressdrops, apparent stresses, etc.for southern Californiaearthquakes and noted thatBorderland events had lowstress drops, especiallycompared to very high stressdrops in the batholith (e.g., theSan Miguel earthquakes).Thus, a given offshore event islikely to have greater slip andgreater seismic moment for thelocal magnitude computed

routinely by SCSN comparedto most onshore events.

SCEC: We’ve heard thatearthquakes produce arumbling sound on land. Whatwould earthquakes sound likeunderwater?

Legg: You should hearearthquakes much better inwater than in air due to theacoustic properties of seawater. In fact, many ships havebeen strongly jolted by a “sea

quake” when in the epicentralregion of significant earth-quakes. At greater distancesfrom the source region,dispersion and attenuationwould remove most audiblefrequencies. But I havebeautiful records of the T-phases of a moderate (M 6)event located offshore Jamaica,and recorded several hundredmiles away in the CaymanIslands region. The T-phase isthe trapped acoustic wave inthe ocean (trapped in the water

Selected Publications, Mark Legg

Legg, M.R., and J.E. Slosson, 1984, Probabilistic approach to earthquake-induced landslide hazard mapping, in Proceed-ings of the Eighth World Conference on Earthquake Engineering, San Francisco, CA, p. 445-452.

Taylor, C.E., M.R. Legg, J.M. Haber, and J.H. Wiggins, 1985, New lifeline multi-scenario seismic risk techniques with amodel application. Civil Engineering Systems, v. 2, p. 77-83.

Legg, M.R., 19886, Earthquake epicenters and selected fault plane solutions of the mid-southern California continentalmargin. Map No. 2B in Greene, H.G., and M.P. Kennedy, editors, Geologic Map Series of the California Continental Margin,California Division of Mines and Geology, Area 2 of 7, (NOS 1206N-15), Scale 1:250,000.

Legg, M.R., 1987, Earthquake epicenters and selected fault plane solutions of the iinner-southern California continentalmargin. Map No. 1B in Greene, H.G., and M.P. Kennedy, editors, Geologic Map Series of the California Continental Margin,California Division of Mines and Geology, Area 1 of 7, (NOS 1206N-16), Scale 1:250,000.

Legg, M.R., and J.M. Haber, 1990, Seismic response of sonic boom-coupled Rayleigh waves: Final Report, U.S. Air ForceSystems Command, Noise and Sonic Boom Impact Technology, OLACHSD/YAH(NSBIT), 246 pp.

Legg, M.R., 1991, Developments in understanding the tectonic evolution of the California Continental Borderland: inOsborne, R.H., ed., SEPM Shepard Commemorative Volume, p. 291-312.

Legg, M.R., 1992, Faulting and seismotectonics in the inner borderland offshore of the Los Angeles Basin in Proceedings ofthe Association of Engineering Geologists Annual Meeting, Long Beach, California, p. 569-578.

Legg, M.R., 1994, Submarine geology of the inner California Continental Borderland of northern Baja California, Mexico.Geological Society of America Map and Chart Series. Scale 1:100,000 (in review).

column, and like the Navysonar, it propagates acrossentire oceans in the Sofarchannel with negligibleattenuation. [Editor's note:"Sofar" is an ocean acoustic wave-guide, related to temperature andsalinity.] Some scientists thinkthat T-phases may be a goodindicator of a tsunamigenicearthquake, but reliabletsunami precursors are stillunproven. ♦

Michael Forrest



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What the Maps Show

The maps show areas in portions of San Francisco, Los Angeles,Orange and Ventura counties that during an earthquake are likelyto be susceptible to landslides and/or to water-saturated groundfailure known as liquefaction.

The first set of preliminary maps encompass 17 communitiesincluding the northern half of San Francisco and SouthernCalifornia, Simi Valley, the Western portion of Santa Monica andan area from Fullerton and Buena Park south to Newport Beach.Each of the six maps is a 7-1/2 minute quadrangle, coveringapproximately 60 square miles at a scale of one inch equals 2,000feet.

Future Maps

Subsequent sets of preliminary maps for portions of Los Angeles,Orange and Ventura counties will be distributed for reviewapproximately every six months until the currently funded totalof 38 maps are produced. The mapping was completed incooperation with the Governor’s Office of Emergency Servicesand the Federal Emergency Management Agency.

Local governments and other interested parties now have untilJanuary 7, 1997 to review and comment on the maps and guide-lines. Once the maps are made official in March 1997, the SeismicHazards Act of 1990 requires local governments use them toidentify areas where geologic or soils investigation are requiredbefore permitting urban development. The guidelines will helpguide cities, counties and consulting engineers and geologists inthe investigation and mitigation of these types of hazards insideand outside the mapped areas.

“These maps identify areas having an increased likelihood ofliquefaction and earthquake-triggered landslides occurring,” saidCharles Real, supervising geologist, department of Conservation,

Local Preliminary Seismic Hazard Zone Maps

out for Review

at a briefing held for local media. “However, we’re not saying theseismic hazards will necessarily occur.”

Where to Find the Maps

The preliminary Seismic Hazard Zone Maps are available tointerested parties for review at cost through two reprographicservices. For details, call the Department of Conservation PublicInformation Offices: Los Angeles (213) 620-3560; San Francisco,(415) 904-7707; or Sacramento (916) 445-5716. Copies of the draftguidelines, a geographic index of the maps released for reviewand other related information are also available through theDepartment of conservation web site:

www. consrv.ca.gov/dmg/shezp

Comments from interested parties or organizations must besubmitted to the State Mining and Geology Board by January 7,1997.

The six preliminary seismic hazard zone maps released includethese cities or portions of cities: the northern half of San Franciscoand in southern California, Anaheim, Buena park, Costa Mesa,Fountain Valley, Fullerton, Garden Grove, Huntington Beach,Moor Park, Newport Beach, Orange, Placentia, Santa Ana, SantaMonica, Simi Valley, Stanton and Westminster.

The California Department of Conservation has one of the oldestgeological surveys in the United States in its Division of Minesand Geology. An integral part of the survey’s purpose is toprevent or minimize injury, death and property damage fromgeologic hazards. The department also safeguards farmland;oversees oil, gas and geothermal wells; regulates mining; studiesearthquakes and landslides; promotes beverage containerrecycling; and manages California’s earth resources. ♦

Ted [email protected]

CDMG Maps on the Web:www. consrv.ca.gov/dmg/shezp

The latest tool to help protect life and property during an earthquake is in the works, thanksto the California Department of Conservation. The department has just distributed sixpreliminary seismic hazard zone maps and draft map guidelines to local officials fortechnical review.

California State Division of Mines and Geology News


341. Song, X. and D. V.Helmberger, The NorthridgeAftershocks, a Source Studywith TERRAscope Data,Geophysical Journal International,submitted, 1996.

342. Kerkela, S. and J. Stock,Compression Directions Northof the San Fernando ValleyDetermined from BoreholeBreakouts, Geophysical ResearchLetters, accepted, 1996.

343. Brocher, T., R. Clayton, K.Klitgord, R. Bohannon, R.Sliter, J. McRaney, J. Gardnerand J. Keene, Multichannelseismic-reflection profiling onthe R/V Maurice Ewing duringthe Los Angeles Region SeismicExperiment (LARSE), Califor-nia, USGS Open File Report 95-228, 1995.

344. Murphy J., G. S. Fuis, T.Ryberg, D. Okaya, M. L.Benthien,.M. Alvarez, I.

Asudeh, W. Kohler, G.Glassmoyer, M. C. Robertson,and J. Bhowmik, Report forthe explosion data acquired inthe Los Angeles Region SeismicExperiment (LARSE), LosAngeles, California, USGSOpen File Report xx-xx, inpreparation, 1996.

345. Okaya, D., J. Bhowmik, G.S. Fuis, J. Murphy, M. C.Robertson, A. Chakraborty, M.L. Benthien, K. Hafner, and J.Norris, Report for Airgun DataAcquired at Onshore Stationsduring the Los Angeles RegionSeismic Experiment (LARSE),California, USGS Open FileReport 96-297, 1996.

346. Okaya, D., J. Bhowmik, G.S. Fuis, J. Murphy, M. C.Robertson, A. Chakraborty, M.L. Benthien, K. Hafner, and J.Norris, Report for EarthquakeData Acquired at OnshoreStations during the Los

More SCEC Scientists' PublicationsMore SCEC Scientists' PublicationsMore SCEC Scientists' PublicationsMore SCEC Scientists' PublicationsMore SCEC Scientists' Publications

The complete SCEC scientists' publications listing is updated and available on a continuous basis.Please contact the SCEC Administrative Office, 213/740-1560, to obtain updated listings from MarkBenthien. Selected publications may be available through a cooperative agreement between SCECand the NISEE-Caltech Library. The Spring quarterly newsletter includes all publications;subsequent issues include newly submitted papers only. Please see Page 11 of this SQN for moreinformation on submitting papers for SCEC numbers.

Angeles Region SeismicExperiment (LARSE), Califor-nia, USGS Open File Report 96-509, 1996.

347. ten Brink, U., G. Miller, T.Brocher, and D. Foster, LosAngeles Region SeismicExperiment - Offshore seismicrefraction data, USGS Open FileReport 96-27, 1996.

348. Davis, P.M. and L.Knopoff, Reply, Journal ofGeophysical Research, accepted,1996.

349. Harris, R. A. and S. M.Day, Effects of a Low-VelocityZone on a Dynamic Rupture,Bulletin of the SeismologicalSociety of America, submitted,1996.

350. Andrews, D. J. and Y. Ben-Zion, Wrinkle-Like Slip Pulseon a Fault Between DifferentMaterials, Journal of Geophysical

Research, accepted, 1996.

351. Gao, S., H. Liu, P. M.Davis, L. Knopoff, and G. S.Fuis, A 98-station SeismicArray to Record Aftershocks ofthe 1994 Northridge Earth-quake, USGS Open-file Report96-xxx, submitted, 1996.

352. Kohler, M. D. and P. M.Davis, Crustal ThicknessVariations in Southern Califor-nia from Los Angeles RegionSeismic Experiment (LARSE)Passive Phase TeleseismicTravel Times, submitted toBulletin of Seismological Societyof America, 1996.

353. Kohler, M. D., J. E. Vidaleand P. M. Davis, ComplexScattering Within D” Observedon the Very Dense Los AngelesRegion Seismic ExperimentPassive Array, submitted toGeophysical Research Letters,1996.

Through a Memorandum of Agreement with SCEC,the Earthquake Engineering Research Library (EERL)of the Caltech National Information Service forEarthquake Engineering (NISEE) serves as the point ofcontact and services to the community at large forearthquake engineering information requests funneledthrough the Southern California Earthquake Center.

SCEC and Caltech's EERL NISEE Library Agreement

The EERL will accept orders as appropriate for SCECmaterials, and forward orders via email for SCECpersonnel. For more information, contact:

Mark BenthienSCEC Outreach [email protected]/740-1560



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The 29th General Assembly of the InternationalAssociation of Seismology and Physics of the Earth’sInterior (IASPEI) will be held in Thessaloniki, Greece,August 18-28, 1997. The purpose of the Assembly is togive the opportunity to scientists from differentdisciplines to meet and exchange ideas about present-dayproblems of the seismological community.

The program will include a workshop on “Educating the PublicAbout Earthquake Hazards and Risk,” with Jill Andrews, SCECKnowledge Transfer Director, and Dr. K. Ioannides (Greece) actingas co-conveners. The call for papers will be issued later in the fall,but if you are interested in participating, please contact JillAndrews for further information at:

SCEC Knowledge TransferUniversity of Southern CaliforniaLos Angeles, California, USA 90089-0742email: [email protected]

The following is a description that will appear in the call forpapers:

Educating the Public About Earthquake Hazards and Risk: An IASPEI GeneralAssembly Workshop Announcement

Session #W9(W15a): Educating the Public About EarthquakeHazards and Risk

Scope: This session will consist of an opening lecture/presentation on Earthquake Education and InformationDissemination (What is it? Why is it important? How do youdo it? What are the benefits?); followed by short presentationsby several volunteers who have successful ongoing outreachprograms; and finally, formation into small breakout groupsto discuss a list of education-information-related topics.

We seek input from participants who have experience with,or interest in, local earthquake response plans; culturalinfluences on earthquake education, preparedness, and/orresponse issues; identification of and interaction with specifictarget groups in both urban and agrarian communities;recruitment of community volunteers to aid in disseminationof earthquake education, awareness, and preparedness;building of mutual beneficial relationships among academic,government, and industry leaders to cultivate communitysupport; use of available aids for information acquisition suchas the Internet; publications; achived data resources; andother earthquake education programs.

Risk Management Solutions(RMS)Hazard/GIS Mapping forInsurance Purposes149 Commonwealth Dr.Menlo Park, CA 94025Tel: (415) 617-6500FAX: (415) 617-6565URL: http://www.riskinc/com

EQE International, Inc.Risk/Safety Engineers - GIS18101 Von Karman Ave., Ste.400Irvine, CA 92715Tel: (714) 833-3303FAZ: (714) 833-3391URL: http://www.eqe.com/

Environmental Risk Companies that use GIS

JHK & AssociatesTransportation SystemsConsultants3500 Parkway Lane, Ste. 600Norcross, GA 30092Tel: (770) 447-6831FAX: (770) 449-7268URL: http://www.jhk.com

Harvard Design & Mapping,Co.Computer Mapping & GISConsultants30 Spinelli PlaceCambridge, MA 02138-1046Tel: (617) 354-0100URL: http://www.hdm.com

Our readers sometimes ask for information on environmental riskmapping companies that use GIS. Here is a partial list:

Dames & Moore, Inc.Environmental & EngineeringServices911 Wilshire Blvd., Ste. 700Los Angeles, CA 90017Tel: 213-683-1560Fax: 213-628-0015URL: http://www.dames.com

Claritas (bought StrategicMapping, Inc.)Developers of Catalyst GIS+,Atlas GIS53 Brown RoadIthaca, NY 14850Tel: 800/876-6732 x2235FAX: 607/266-0425URL: http://www.claritas.com

Public Technology Inc.1301 Pennsylvania Ave. NW,Ste. 800Washington DC, USA 20004Tel: (800) 852-4934FAX: (202) 626-2498URL: http://pti.nw.dc.us

Geo InSight International,Inc.GIS/Mapping ConsultingFirm2800 Woodlawn Dr., Ste. 253Honolulu, HI, 96822Tel: (808) 539-3807FAX: (808) 539-3810


The first SCEC Science Seminar of the FallSeason was held at U.C. Los Angeles from onThursday, September 19. The topic was“Modeling Ground Motion from LocalEarthquakes.” The following questions wereaddressed:

How well we can presently match observedseismograms?

How adequate are available models of sourcecomplexity, propagation velocity, and siteeffects?

How well can source, path, and site effects bedistinguished from one another?

How coherent is the wave field as a function offrequency at the surface and at the base of thesoil?

What improvements in observationalcapabilities will most effectively improve ourabilities to predict ground motion in the nearfuture?

The next Science Seminar is October 17, hostedby USC. Subject will be "Progress Report onthe Database of Fault Parameters."

Science Seminar NewsScience Seminar NewsScience Seminar NewsScience Seminar NewsScience Seminar News

Clockwise from top right:

1. Sue Hough (USGS), Leon Teng (USC),Yehuda Ben-Zion (USC), Yan Kagan (UCLA),and Heidi Houston (UCLA).

2. Norm Abrahamson and David Jackson.

3. Hong Liu, UCLA, was a featured speaker.

1.

2.

3.



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he Southern California Earthquake Center will host the Tenth Biennial meeting of the U.S.-Japan NaturalResources Panel on Earthquake Research (UJNR), in Los Angeles, California, November 12-14, 1996. By virtue ofprotocol, the meeting is by invitation only. Research reports and summaries will be presented by representatives andresearch scientists of agencies on both sides of the Pacific. The principal theme of the meeting will be “U.S.-JapanPartnership in Earthquake Disaster Mitigation Research,” and will build on the recently agreed upon EarthquakeDisaster Mitigation Partnership between our two countries as a part of the Common Agenda for Cooperation inGlobal Perspective recently signed by President William J. Clinton and Prime Minister Ryutaro Hashimoto.

This UJNR panel is the primary government-to-government connection between researchers in the U.S. and their counterparts in thescience and technology agencies in Japan for a broad spectrum of earthquake-related activities. The U.S. panel will play a central rolein the formulation and implementation of the Earthquake Disaster Mitigation Partnership. In the next issue of SQN, we will highlightthe proceedings of the meeting and provide more information on the Earthquake Disaster Mitigation Partnership.

SCEC to Host U.S.-Japan Natural Resources

Panel on Earthquake Research

T

Session Topics

GPS/SAR— New space technologies for evaluating earthquake potential— Continuous GPS array in southern California— Modeling of velocity field in southern California— Using SAR for observing crustal strain

STRONG GROUND MOTION— New observations and methodologies for predicting strong shaking— 3-D wave propagation in LA basin— Focusing effects in LA basin— Character of ground motions from large earthquakes in LA— Phase III time history scenarios

URBAN SEISMIC HAZARDS— Faulting and Seismic Potential in LA Basin— Mechanics of thrust faulting in LA basin — the thick skin model— Mechanics of thrust faulting in LA basin — an alternative model— Integrated approach to seismic hazard analysis

STRATEGIES FOR COOPERATIVE PROJECTS UNDER THECOMMON AGENDA— Time-dependent stress transfer— The 1700 Pacific NW earthquake and tsunami— Fault-zone drilling— Realtime Seismology— Coordination of emergency response

The US Geological Survey (USGS) has just released a summaryreport on the January 1994 Northridge, California, earthquake.The report, USGS Response to an Urban Earthquake -- Northridge '94,includes the findings of approximately 100 scientific and engi-neering investigators, and describes activities of the USGS andmany other governmental agencies and private companies in theimmediate aftermath of the earthquake and during ensuing workthrough early 1996.

The report describes the roles and actions of the USGS, itscooperators, and other entities in response to the earthquake, the

earthquake's setting and impacts, ground response, groundfailures and landslides, structural damage to buildings andfreeways, seismic hazards assessments for the future, methods ofcommunicating scientific information, and policies and plans forseismic safety.

Electronic versions of the report are currently available asPortable Document Format (PDF) and HyperText MarkupLanguage (HTML) files on the World Wide Web at the followingURL:

http://geohazards.cr.usgs.gov/northridge/

Northridge Earthquake Reveals Lessons for Modern Cities

USGS News

An urban earthquake hazards field trip also will be scheduled.


Berkeley, Calif. — In an articlefrom the Public Information Officeof the University of California atBerkeley, Robert Sanders recentlyreported that two UCB geophysi-cists have used a Los Alamos T3Dto solve a long-standing problem ingeology: why the Earth’s crustalplates are so large.

Theories of fluid heating andconvection say the surface shouldbe broken into pieces no largerthan about 3,000 kilometers across.Instead, the plates are much larger.For example, the Pacific platecovers nearly 13,000 kilometers atits widest. The scientists found thatif one assumes that the viscosity ofhot rock in the Earth’s interiorincreases by a factor of 30 from topto bottom, then simulatedconvective flow allows the tectonicplates to conform to their observeddimensions.

“This is a fundamental discoveryof fluid dynamics which brings usvery close to solving a majorproblem of geodynamics,”observed Mark Richards, professorof geophysics at the University ofCalifornia at Berkeley, in Sanders’article.

For the results to be noted, the

Geophysicists Use T3D to Revise Plate Tectonics TheoryGeophysicists Use T3D to Revise Plate Tectonics TheoryGeophysicists Use T3D to Revise Plate Tectonics TheoryGeophysicists Use T3D to Revise Plate Tectonics TheoryGeophysicists Use T3D to Revise Plate Tectonics Theory

geophysicists monopolized 64nodes of the Los Alamos NationalLaboratories’ T3D for nearly threeweeks in a 3-D simulation ofEarth’s mantle, which underlies thesurface crust or lithosphere andextends approximately 2,700kilometers down. Richards and UCBerkeley graduate student Hans-Peter Bunge will detail theprocedure in an article scheduledfor publication in the Oct. 1 issue ofGeophysical Research Letters. Theypreviously described a moreidealized model in the Feb. 8, 1996,issue of Nature.

“Until now the explanation hasbeen that the plates are stiff andhave high strength, so they makebig rafts that only sink in a fewplaces,” Richards commented toSanders. “We’ve turned that wholeargument on its head. If you try tomodel that, it doesn’t really workout.”

But by radically simplifying themodel of Earth’s interior to includeonly viscosity, the problem wascracked. This effect has onlyrecently been established fromseismic reflection studies, Richardsnoted. The researchers alsoassumed that viscosity jumpsrapidly at a depth of approxi-

mately 660 kilometers. Bunge’ssimulation was based on an earliermodel by postdoctoral fellow JohnBaumgardner. “Assuming a 30-times increase in viscosity causes adramatic change over what you getwhen you assume a uniformviscosity in the mantle,” hecommented to Sanders. “Instead ofisolated point-like cold blobsdropping into the interior, thepattern changes to long, linearstructures sliding into the interiorthat look like subduction zones.This tells us that what we see ismore related to the deep mantlethan to the plates.”

“Once we included the effects ofchanging viscosity, we got prettymuch the Earth,” Richards said.“The deep mantle is perfectlyhappy with that scale of convec-tion, and the surface plates followthe convecting system in themantle, rather than vice versa. Theamazing thing is that such a simpleeffect, a viscosity contrast betweenthe upper and lower mantle, hassuch profound influence on whatwe find at the surface. The size ofthe continents is governed by thiseffect and not by the structure andstickiness of the plates.”

The model also explains the

stability of the Earth’s hotspotssuch as the Hawaiian and ReunionIslands, Yellowstone, and Iceland.These upwellings are rootedsolidly in the very viscous deepmantle, near where it borders thecore, and can’t move.

Bunge and Richards plan toimprove their model so that itreflects even more of the details ofthe Earth’s interior. Bunge is alsodeveloping a way to calculate themodel using a cluster of worksta-tions, rather than using expensivesupercomputing resources. Thework was supported by a grantfrom National Science Foundationand by the Institute of Geophysicsand Planetary Physics at LosAlamos. Computer time wasprovided by the AdvancedComputing Laboratory atLANL. ♦

From SCIENCE AND ENGINEER-ING NEWS, 09.13.96. HPCwire hasreleased all copyright restrictions forthis item. Please feel free to distributethis article to your friends andcolleagues. For a free trial subscrip-tion, send e-mail to:[email protected].

Rahul Bahadur([email protected])

Tom Henyey, Center Director, with SCEC scientist and San DiegoState University professor Tom Rockwell, will lead a group ofSCEC affiliates on a field trip to examine the Palos Verdes fault onOctober 25, 1996. Michael Forrest, SQN Associate Editor, hascompiled another provocative book to describe the trip. Thisversion will feature a specific guide, with maps, to providereaders with the information necessary to conduct their own trip.

The book will cover the character and seismicity of the PalosVerdes fault, and the fault zone origins. The field guide willfeature stops along the winding road to Malaga Cove, with

intriguing information about the structure of the fault and thehistory of fault movement. A chapter on the Los Angeles Harborwill be included since the trip features a yacht tour of the Harbor.

The book is due for printing in mid-November. For information onhow to obtain a copy, please contact SCEC Knowledge Transfer:

Mark BenthienOutreach Specialist

tel 213/740-1560fax 213/740-0011

email: [email protected]

Palos Verdes Fault Book to be ReleasedPalos Verdes Fault Book to be ReleasedPalos Verdes Fault Book to be ReleasedPalos Verdes Fault Book to be ReleasedPalos Verdes Fault Book to be Released



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Earthquake Hazards Reduction FellowshipAnnounced

Under a cooperative agreement with FEMA, the EarthquakeEngineering Research Institute offers the 1997 ProfessionalFellowship to provide an opportunity for a practicing professionalto gain greater skills and broader expertise in earthquake hazardsreduction, either by enhancing knowledge in the applicant's ownfield, or by broadening his or her knowledge in a related, butunfamiliar discipline. The fellowship provides a stipend of$30,000, commencing January 1997, to cover tuition, fees, reloca-tion and living expenses for a six-month period. Applicants mustprovide a detailed work plan for a research project that would becarried out in the six-month period. Candidates may obtain anapplication form from:

EERI499 14th Street, Suite 320Oakland, CA 94612-1934Telephone: 510/451-0905

Fax: 510/451-5411e-mail: [email protected]

PASSCAL is sponsoring a two day short course on high resolu-tion seismic reflection techniques to be given by Don Steeples.The course will be conducted at Stanford on Dec 13-14, 1996. It isdesigned for Principal Investigators who have little or no experi-ence in this area, but who would like to utilize the new PASSCALmulti-channel reflection acquisition system either on experimentsor for class room purposes.

The course will cover the basics of data acquisition and processingand have some limited field work. A comprehensive set of coursenotes will be available to all attendees. In order to provide themaximum “hands-on” experience, the course will be limited to 20students. PASSCAL can provide a limited amount of financialsupport if necessary.

Registration requests should be submitted by filling in the formon the PASSCAL Web site:

http://www.iris.edu/passcal/course.form.html/

Priority will be given to faculty and research staff. However, onOctober 1, any remaining slots will be open to students who haveapplied. Questions should be addressed to Jim Fowler([email protected]). ♦

PASSCAL High ResolutionPASSCAL High ResolutionPASSCAL High ResolutionPASSCAL High ResolutionPASSCAL High Resolution

Seismic Short CourseSeismic Short CourseSeismic Short CourseSeismic Short CourseSeismic Short Course

National Disaster Medical SystemConference Scheduled

The National Disaster Medical System (NDMS) is sponsoring itsannual 1997 conference in Tampa, Florida. The main conference willbe held May 5 - 7 and the pre-conference courses will be conductedMay 3 - 4, 1997.

The Conference will focus on delivering health and medical servicesin catastrophic disasters and will be held at the Hyatt Regency atTampa City Center, in Tampa, Florida. For additional information,please contact NDMS on 1-800-USA-NDMS, extension 444.

The Conference will feature tracks focusing on the following issues:

Public HealthPlanning, Management and CoordinationClinical MedicineField Response, andHealth Care Facilities.

The following training courses will be offered prior to and duringthe conference: Communications, Mass Fatalities, Mass Casualty,Moulage, Exercise Design and Incident Command System (ICS).Full accreditation for continuing education is anticipated for thesecourses and the main conference.

The SCEC Quarterly Newsletter seeks contributions from SCEC research-ers. Short summaries of current work in progress by researchers in theeight SCEC working groups will be published each issue. Please followthese guidelines:

Your contribution must be a project which falls into one of the eightworking groups:

Group A, Master Model: David Jackson, group leaderGroup B, Ground Motion Modeling: Steve Day, group leaderGroup C, Earthquake Geology: Kerry Sieh, group leaderGroup D, Subsurface Imaging and Tectonics: Rob Clayton, group leaderGroup E, Crustal Deformation: Ken Hudnut, group leaderGroup F, Regional Seismicity and Source Processes: Egill Hauksson,group leaderGroup G, Physics of the Earthquake Source: Leon Knopoff, group leaderGroup H: Engineering Applications: Geoff Martin, group leader

The length of the article should be about 500-750 words of text, written ata 4-year (Bachelor’s) college degree level. If you use technical phrases orjargon, please include brief definitions. (Although our readers are well-educated experts, they are likely not up to speed in your earth-science orengineering-related field. Definitions help.) The text should cover adescription of your research project and how it fits with the workinggroup's goals; names of principal investigators, post-docs, graduate orundergraduate students; and the important findings. If you would like toinclude figures, graphs, or photos, we can incorporate them into thearticle. We can either scan in original figures or photos, or receive themfrom you via the Internet. For information on how to best transfer yourfigures or photos, contact Mark Benthien at ScecInfo.usc.edu.

Please email your contributions to:[email protected]

SQN Seeks Contributions from Scientists


.

EQIP EstablishesEQIP EstablishesEQIP EstablishesEQIP EstablishesEQIP Establishes

EQNET HomeEQNET HomeEQNET HomeEQNET HomeEQNET Home

Page and WebPage and WebPage and WebPage and WebPage and Web

SiteSiteSiteSiteSite

The Earthquake Information Providers'Group (EQIP, pronounced "equip") nowhas a Web site under construction. Called"EQNET" (Earthquake Hazards MitigationInformation Network), the site links to 43sites featuring resources related toearthquake hazards mitigation. Check out:

http://www.eqnet.org

The page has an alphabetic listing ofinformation sources (linked); informationsources by subject; bibliographic resources(indexes, libraries, etc.); images, multime-dia and computer software providers; anda page which describes the mission of theEQNET Web site working group.

The working group, comprised of volun-teer Earthquake Hazard MitigationInformation Providers, has created thehome page and site and will endeavor toassist the community of earthquakeinformation providers with Web-relatedsupport.

Members of the EQNET working groupinclude:

Patricia Coty, Chair (NCEER)Jill Andrews (SCEC)Clifford Astill (NSF)Jim Buika (FEMA Region IX)Dave Butler (NHRAIC)Karen Gahagan (IIPLR)Steve Ganz (WSSPC)Lind Gee (UCBSS)Chuck James (UCB-EERC)Scott McAfee (OES)Dick McCarthy (CSSC)Sarah Nathe (OES)Chris Rojahn (ATC)Doroty Tao (NCEER)Jeanette Zerneke (UCB)

IDNDR Internet Conference: Solutions for Cities atRisk to Disasters, 26 August - 25 October 1996

The internet conference was part of the 1996 public awareness campaign, Cities at Risk,organized by the United Nations Secretariat for the International Decade for NaturalDisaster Reduction, and implemented jointly with many organizations around the world.In August, 1996, IDNDR announced its Internet Conference. The following is a summary ofthe purpose and content of the conference, and information on how you can access theresults.

The IDNDR Internet Conference on Solutions to Cities at Risk was a forum for debate. Inthis conference, participants learned what communities around the world are doing toprotect themselves from disasters; asked questions to those directly involved in cityprograms, to see how their activities could be adapted; presented urban disaster mitigationexperiences for discussion and feedback; consulted experts in many different professionsabout disaster mitigation issues.

Conference proceedings will be published as a “Solutions for Cities at Risk” publicationin 1997 (pending sponsorship). Organizers of the Conference were the United Nations -International Decade for Natural Disaster Reduction (IDNDR) Secretariat and the IDNDRRegional Office, Latin America/Caribbean.

The Host was QUIPUNET, an NGO which promotes education via the Internet.QUIPUNET was host of recent Internet conference on Kobe Earthquake and its lessons. Theconference address on the World Wide Web: http://www.quipu.net/risk/

Participants included city administrators, National IDNDR Committees, UN specialisedagencies, inter-governmental and non-governmental agencies, scientific organizations,universities, national ministries, and the private sector.

Campaign materials to carry out local activities are available:

- Publication: Cities at Risk (40pp, English, Spanish, French, Italian) - Poster: Making Cities Safer (English, Spanish, French, Italian) - Flyer: International Poster Contest (English, Spanish, French) - Flyer: Guidelines for Local Organizers (English, Spanish, French) - Flyer: Facts and Figures (English, Spanish, French) - Flyer: Activities for Children flyer (English, Spanish, French) - Booklet for children: Learning about Natural Disasters (English, Spanish, Italian, French, Russian, Chinese, Hindi, Farsi, Macedonian) ($2.50/copy) - Stop Disasters Magazine (English, Spanish, French, Italian; abbreviated versions in Chinese and Russian)

For more information, contact:

International Decade for Natural Disaster Reduction (IDNDR) SecretariatUN Department of Humanitarian AffairsPalais des Nations1211 Geneva 10SwitzerlandTel: (41 22) 798 6894, Fax: (41 22) 733 8695E-mail: [email protected]

Quipunet Home Page: http:// www.quipu.net

IDNDR Home Page: http://hoshi.cic.sfu.ca/hazard/idndr.html



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CalendarCalendarCalendarCalendarCalendar

October, 1996

17 SCEC Science Seminar, "Progress Report on the Databaseof Fault Parameters," 1pm - 5pm, Crowne Plaza Hotel, LosAngeles. For more information, contact [email protected].

20-22 SCEC Annual Meeting, Palm Springs, California. Call213/740-5843 for more information.

20-22 Association of Contingency Planners (ACP) NationalSymposium, San Antonio, Texas. Call 512/463-3950 and askfor Tommye White for more information.

25 SCEC-Sponsored field trip with Dr. Tom Henyey, SCECDirector, and Dr. Tom Rockwell, San Diego State University.We will spend the day inspecting the Palos Verdes Fault zone.The trip is full but we'll be scheduling a duplicate trip inFebruary, 1997. Stay tuned!

28-31 Geological Society of America (GSA) Annual Meeting,Denver, Colorado. Meeting will include sessions on seismic-ity of North America and on numerous other geologichazards. Contact: GSA, 3300 Penrose Place, Boulder, CO80301; 303/447-2020; 800/472-1988.

30-31 A Two-Day Workshop: Exploring Options for SeismicZonation in the City of Los Angeles. Co-sponsored by theCity of Los Angeles, CDMG and SCEC. Call 213/740-1560for more information.

November, 1996

5-7 3rd US-Japan Conference on Corporate EarthquakePrograms, San Jose, CA. Information: Steven Vukazich, 408/924-3858, fax 408/924-4004, e-mail: [email protected].

12-14 Tenth U.S.-Japan Natural Resources Committee onEarthquake Prediction Technology, by invitation only.Contact: J. Dieterich, USGS, email:[email protected], or Bill Ellsworth, USGS, email:[email protected].

December, 1996

3-5 International Conference and Exposition on Natural

Disaster Reduction, American Society of Civil Engineers,Sponsor, Washington, D.C. Contact: Natural DisasterReduction '96, ASCE, 345 East 47th Street, NY, NY, 10017;800/548-2723; email: [email protected].

6-7 SCEC-Sponsored Field Trip with Dr. Kerry Sieh. Wewill inspect the southern San Andreas Fault system. We’llbegin in San Bernardino and head south, ending up inPalm Springs. Don’t miss this opportunity to learn moreabout the largest fault in California! Call 213/740-1560 formore information.

15-19 American Geophysical Union Annual Meeting, SanFrancisco, CA. Fax 202/328-0566; email:[email protected]

January, 1997

15-17 Fifth U.S./Japan Workshop on Urban EarthquakeHazard Reduction. Sponsored by EERI and JapanInstitute of Social Safety Science (ISSS). Los Angeles, CA."Recovery and Reconstruction from Recent Earthquakes:Implications for Urban Earthquake Hazard Reduction."Contact EERI, phone 510/451-0905; fax 510/451-5411.

February, 1997

20 SCEC Science Seminar, Caltech. Subject to be an-nounced.

March, 1997

20 SCEC Science Seminar, U.C. San Diego. Subject to beannounced.

April, 1997

9-11 Seismological Society of America 92nd AnnualMeeting, Honolulu, HI. Contact: [email protected] or WWW: http://www.soest.hawaii.edu/ssa97.html

17 SCEC Science Seminar, U.C. Los Angeles. Subject tobe announced.

POSTPONED UNTIL FURTHER NOTICE: SCEC Annual media workshop, "Earth-quakes and the Media." Goal of the workshop is to identify needs of radio, television, printand wire representatives in the context of SCEC's capabilities. Call 213/740-1560 for moreinformation.


See "On Line Resources" on Page 31

Current Southern California Seismic Network(SCSN) Weekly Earthquake Reports:http://www.scecdc.scec.org/earthquakes/current.txt (text)http://www.scecdc.scec.org/earthquakes/current.gif (map)

SCSN Weekly Earthquake Reports back to January1993:http://scec.gps.caltech.edu/ftp/ca.earthquakes

Caltech/USGS Seismocam: Waveform displays ofdata only 30 seconds old:http://scec.gps.caltech.edu/seismocam/

Earthquakes in Southern California:Includes aftershock maps, animations of aftershocksequences and rupture models, and a clickable map ofhistoric Southern California earthquakes and Los AngelesBasin earthquakes. Main Page:http://www.scecdc.scec.org/eqsocal.html

Southern California Clickable earthquake map:http://www.scecdc.scec.org/clickmap.html

Los Angeles Basin Clickable earthquake map:http://www.scecdc.scec.org/laseiskiosk.html

LARSE home page:http://www.scecdc.scec.org/larse.html

USGS OFR 96-85, Data Report for 1993 Los AngelesRegion Seismic Experiment, Southern California: APassive Study from Seal Beach Northeastwardthrough the Mojave Desert. http://www.scecdc.scec.org/larse/93title.html

USGS OFR 95-228, Multichannel Seismic-Reflection Profiling of the R/V Maurice EwingDuring the Los Angeles Region SeismicExperiment (LARSE), California.http://www.scecdc.scec.org/larse/LMtitle.html

USGS Response to an Urban Earthquake --Northridge '94, electronic version:http://geohazards.cr.usgs.gov/northridge/

Earthquake Information Resources On LineEarthquake Information Resources On LineEarthquake Information Resources On LineEarthquake Information Resources On LineEarthquake Information Resources On Line

The Nevada Seismological Laboratory

http://www.seismo.unr.edu

This site offers information on current earthquakes and itsresearch and teaching programs. Users can access lists,maps, and seismogram data from the latest earthquakes, andcan report any events they have felt. There arebackground geologic and seismicity maps, and on-linesearching of earthquake catalogs. General information isavailable on-line in contact lists, brochures, geophysicsdegree program information for students, and courses inearthquake fundamentals and scientific visualization.

John Louie([email protected])

Up-to-the-minute Southern CaliforniaEarthquake Map:This site takes the earthquake locations broadcast via e-mailfrom Caltech and makes a map of the last approximately500 earthquakes. It is automatically updated and works forJava-enabled browsers only.

http://www.crustal.ucsb.edu/scec/webquakes/

Understanding EarthquakesA general interest site that includes an earthquake quiz, arotating globe showing earthquake locations, famousaccounts of earthquakes, and similar features.

http://www.crustal.ucsb.edu/~grant/understanding/

Santa Barbara Earthquake HistoryHistorical accounts and photographs relating to earth-quakes that have affected Santa Barbara County, California.

http://www.crustal.ucsb.edu/~grant/sb_eqs/

For further information, contact the author:Grant LindleyInstitute for Crustal StudiesUniversity of CaliforniaSanta Barbara CA [email protected] 805-893-8649tel 805-893-8437

SCEC Data Center Pages



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Earthquake Information Resources On Line, cont.Earthquake Information Resources On Line, cont.Earthquake Information Resources On Line, cont.Earthquake Information Resources On Line, cont.Earthquake Information Resources On Line, cont.

SCEC WWW URLhttp://www.usc.edu/go/scec

SCEC on the Internet

SCEC Knowledge Transfer and Education Programsare reachable via electronic mail.

Ask general questions, make requests, send usinformation for use in our resource center or forconsideration for publishing in the next newsletter.

[email protected]

Other WWW Sites for ExplorationSCEC World Wide Web Home Page

EQNEThttp://www.eqnet.org/

Recent Quakes (with a great map viewer)http://www.civeng.carleton.ca/cgi-bin/quakes

Annual Southern California NetworkBulletins from 1991 - PresentThe bulletins are now available on the Web (minus thefigures). They describe the activities of the USGS PasadenaField Office and include a summary of annual seismicity and alist of magnitude 3.0+ events each year. Contact Lisa Wald,USGS Pasadena, e-mail [email protected] for information.

http://aladdin.gps.caltech.edu/lisa/NETBULLS/netbull_list.html

USGS Web Sites with EarthquakeInformation and More

General USGS site: http://www.usgs.govNational Earthquake Information Center: http://gldss7.cr.usgs.gov/Earthquake Information: http://geology.usgs.gov/quake.htmlUSGS Menlo Park: http://quake.wr.usgs.gov/USGS Pasadena: http://www-socal.wr.usgs.gov

The Council of the National SeismicSystem Merged Earthquake DatabasesThe databases can be tracked down with hypertext jumpsthrough two Web sites:

http://www.geophys.washington.edu/cnss.cat.htmlandhttp://quake.geo.berkeley.edu:80/cnss

The first address has a very long current catalog that is hard toread, but prints out fairly legibly.

Jack Popejoy, KFWB News Radio 98

SCEC Volunteer Needed to Aid the“Ask a Scientist” Project

A new web site is under construction. It is called “Ask aScientist,” and will provide email contact to K-12 teachers andstudents with scientists from all disciplines. The HumboldtCounty Office of Education is developing the web site “to assistK-12 students and teachers in locating quality science resources onthe internet.” This is the science portion of a project funded by theCalifornia County Superintendents Educational ServicesAssociation and has been given the name “Schools of CaliforniaOnline Resources in Education,” or S.C.O.R.E.

The site is located at: http://intergate.humboldt.k12.ca.us/score/

Scientists interested in participating should contact Dan Scofieldat: [email protected]

Requests and questions from high school students appear on aregular basis on many scientists’ email. To provide a mechanismfor sharing the load, SQN would like to hear from any volunteerswho could perform as a SCEC intermediary, whose function is toscreen requests, possibly guide students or and to appropriatelydirect them to sources of information. If you are interested, pleasecontact:

Mark BenthienSCEC Outreach Specialist and [email protected]

SQN Ed.


SCEC Board of DirectorsSouthern CaliforniaEarthquake Center

Administration

Center Director - Thomas HenyeyScience Director - David JacksonAdministration - John McRaney

Education - Curt AbdouchKnowledge Transfer - Jill Andrews

Outreach Specialist - Mark BenthienAdministrative Ass't - Sue Turnbow

Write, Telephone, email, or fax:

Southern California Earthquake CenterUniversity of Southern CaliforniaUniversity ParkLos Angeles, CA 90089-0742Tel: 213/740-1560Fax: 213/740-0011Email: [email protected]

T o S u b s c r i b eT o S u b s c r i b eT o S u b s c r i b et o t h e S C E Ct o t h e S C E Ct o t h e S C E C

Q u a r t e r l y N e w s l e t t e rQ u a r t e r l y N e w s l e t t e rQ u a r t e r l y N e w s l e t t e rOne year's subscription is $25.00.Please make payment by check, moneyorder, or purchase order, payable to"University of Southern California/SCEC." Please do not send currency.Price includes postage within the U.S.Overseas airmail costs or specialcourier services will be billed. SCECscientists and students and affiliatedagencies receive this newsletter free ofcharge.

Bernard Minster, Vice ChairmanScripps Institution of Oceanography

University of California, San Diego

Charles SammisUniversity of Southern California

Leonardo SeeberColumbia University

David Jackson, ChairmanUniversity of California, Los Angeles

Ralph ArchuletaUniversity of California,

Santa Barbara

Robert ClaytonCalifornia Institute of Technology

James MoriUnited States Geological Survey

World Wide Web: Geodetic Information

GPS Time Series and SCIGN Map:http://sideshow.jpl.nasa.gov/mbh/series.html

SCEC Data Center Geodetic Information:http://www.scecdc.scec.org/scign

JPL Web Site: http://milhouse.jpl.nasa.gov/

KFWB Radio Webservice:

This site features an earthquake page and links to the SCECHome Pages and to the SCEC Data Center: http://kfwb.com

The earthquake button leads you to:http://kfwb.com/eqpage.html

The SCEC Portable Broadband Infrastructure Centerand other geophysics and earthquake informationsites with links:

http://www.crustal.ucsb.edu/scec/pbichttp://www.crustal.ucsb.edu/scec/smdbwww.crustal.ucsb.edu

For more information, contact:Aaron J. Martin([email protected])

Seismo-surfing the Internethttp://www.geophys.washington.edu/seismosurfing.html

Southern California Earthquake CenterUniversity of Southern CaliforniaLos Angeles, CA 90089-0742

ADDRESS CORRECTION REQUESTED

SCEC Quarterly Newsletter

SCEC Quarterly Newsletter (SQN) is published quarterly bythe Southern California Earthquake Center, University ofSouthern California, University Park, Los Angeles, CA90089-0740, USA, telephone 213/740-1560 or 213/740-5843,fax 213/740-0011, e-mail: [email protected]. Please sendrequests for subscriptions and address changes to theattention of SQN Editor.

SubscriptionInformation:see page 31

Inside this issue:

Feature ArticlesWhat is SCEC? Page 2SCEC's Sixth Year Site Review Page 3NSF Director Lane Encourages Outreach Page 6SCEC Knowledge Transfer Page 6CDMG Hazard Maps out for Review Page 20Geophysicists Revise Plate Tectonics Theory Page 25IDNDR Internet Conference Page 27

SCEC DepartmentsFrom the Center Directors Page 2Quarter Fault: San Cayetano Page 12Visit with SCEC Scientist Mark Legg Page 15Recent Publications Pages 11 & 21SCEC Science Seminar News Page 23

Activities ReportsSCEC Research: Desert Explosions Page 8Open Letter from John McRaney Page 10San Andreas Field Trip Announcement Page 14IASPEI General Assembly Workshop Page 22SCEC to Host UJNR Panel Page 24Palos Verdes Fault Guide Release Page 25Earthquake Info Resources On Line Pages 29- 31Calendar Page 28

Non-Profit OrganizationU.S. Postage PaidUniversity ofSouthern California

Contributing Writers:Mark Benthien, SCECMichael Forrest, USCThomas Henyey, USC/SCECYong Gang Li, USC/SCECJohn McRaney, USC/SCECTed Smith, CDMG

Photographs and Figures:Dolan, et al. (p. 13)M. Forrest (pp. 8, 9, 23)T. Henyey (p. 2, 4)M. Legg (pp. 15, 17)T. Rockwell (Cover; p. 13)

Photo and figure enhance-ment: Mark Benthien

Editor, Writer, and Production Artist: Jill AndrewsAssociate Editor: Michael Forrest

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