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SCEC Newsletter This Issue Contributors Quarterly Newsletter Volume 5, Number 1 Southern California 2 Earthquake Center Exciting Initiative: EarthScope 3 Interview: John Anderson 9 Hough: Best-Laid Plans 10 Fault: Rose Canyon 16 Evaluating Liquefaction Hazard 18 Profiles: SCEC Interns 24 Benthien: A Funny Thing 26 Post-Earthquake Planning Seminar 29 Teachers Sacrifice for Science S C EE C From the Center Directors EarthScope—a New and Exciting Initiative By Tom Henyey Center Director Science Director The Earth Sciences Division proving our understanding of (EAR) at the National Science the earthquake process. Foundation (NSF) is working • How do faults and earth- densification of geodetic and with the scientific community Particularly relevant to earth- quakes interact with one seismic instrumentation along to orchestrate a new and poten- quake physics is the geodetic another in time and space? the northern San Andreas, and tially exciting scientific (strain) component of the initia- perhaps other faults, for in- initiative called EarthScope. tive, referred to as the Plate The PBO would measure defor- creased spatial resolution; 3) EarthScope would consist of Boundary Observatory (PBO). mation over a broad spectrum the linking of the major earth- large arrays of state-of-the-art The PBO is expected to consist of spatial and temporal scales quake-producing zones to of a mix of GPS instrumenta- and provide sufficient resolu- cover the seismogenic part of tion, strainmeters, and InSAR tion to constrain any transients the plate boundary; and 4) We would be in a posi- images that can be used to associated with short-wave- increasing the access to InSAR tion to detect precursory address such questions as: length phenomena such as data. strain transients that may earthquakes and magmatic prove practical for • How is deformation accom- activity. A close integration of While the main focus of the forecasting earthquakes modated within a plate PBO would be to gain a basic and volcanic eruptions. boundary zone? understanding of plate bound- The plate boundary ary processes, it also would • What controls the spatial observatory is expected provide information of practical seismic and geodetic instru- characteristics of plate to consist of a mix of value. In particular, we would mentation, much of it focused boundary deformation? GPS instrumentation, be in a position to detect pre- on active tectonics of the Pa- strainmeters, and InSAR cursory strain transients, should cific/Juan de Fuca-North • What controls temporal images. they occur, that may prove American plate boundary of the variations in a plate bound- practical for forecasting earth- western U.S. A deep earth ary? quakes and volcanic eruptions. observatory along the San seismometers, GPS, Let’s hope EarthScope becomes Andreas fault at Parkfield also • Are there deformation strainmeters, and InSAR is a reality—it’s our opportunity to would be part of EarthScope. transients that propagate necessary to provide uniform add significant new resources within the plate boundary strain-rate sensitivity at plate- to the entire earth sciences SCEC is one of several major zone? motion strain rates and across community. NSF-funded programs helping the temporal band from several EAR shepherd the initiative • What is the relationship Hertz to a decade. through the Foundation’s ad- between vertical and Editor’s Note: As this issue was ministrative structure. If funded horizontal tectonics? Thus, the establishment of a prepared, Bernard Minster was over the next several years, fully capable PBO will require announced as the new Acting these new facilities would be • How does plate motion progress in four areas: 1) a Science Director for SCEC. an important resource for a ultimately produce an more effective integration of Please see page 35 for the future earthquake center and earthquake? strainmeters and GPS for a truly administrative structure as of for achieving the goal of im- broadband observatory; 2) the August 1, 1999. 2 Southern California Earthquake Center Quarterly Newsletter Vol. 5, No. 1, 1999 Interview with SCEC Scientist John Anderson Interviewed by Jill Andrews John Anderson, director of the neered structure when the fault Seismological Laboratory at the mapped by geologists breaks.” University of Nevada at Reno So “synthetic” seismograms are and member of the SCEC board the goal. We want them to be of directors, is interviewed here so realistic that engineers can about his work in strong motion use them. But we also want California Earthquake Center, normally feel. So accelerograph seismology, especially in the them to be based on sound specifically, your work on the data is getting more interesting context of the SCEC mission. understanding of the physics of Phase III Report (need official to network seismology, and the the earthquake process so that name for this report). How distinction between strong SCEC: You and your group they will be reliable. would you define the term motion seismologists and others appear to be in a “transition “strong motion seismologist” to is getting blurred. Still, the zone” between basic research SCEC: How can this be someone who doesn’t have a original focus of strong motion and tangible products—in other achieved? background in geophysics? seismology is to understand words, you are trying to find ground motions that are strong results that are immediately JA: We have to bring in source JA: I’d define strong motion as enough to cause damage. useful. What have you found so physics, wave propagation, and earthquake motions that are That’s still true. far, and who will use the results scattering caused by the com- strong enough to feel. Strong of your work? plexity of the Earth. At the least, motion seismologists might also SCEC: How completely has the we have to take what others be recognized by one type of digital accelerograph replaced JA: First, I think it is not as far have learned and incorporate it instrument that is essential for the old analog instrument? Do from basic seismic research as into our models. On the other their research. They must have you still use both? accelerographs, which are distinguished from the instru- JA: The most common analog Nearly every task SCEC identified for southern ments used by most other strong motion accelerograph in California ought to be done in Nevada, in Utah, seismologists in that they stay the world, the Kinemetrics near New Madrid and every other seismic zone in on scale in even the strongest SMA-1, was discontinued many the U.S. shaking but can’t detect weak years ago, but there are still earthquakes that are easily large numbers of them out in observed using higher gain the field. The data they produce it may appear. I’m thinking of a hand, one can hope that our instruments. Twenty years ago, is very good data, but it’s less vision for strong motion seis- research; i.e., the constraints on before the digital revolution in convenient to use because they mology given in 1980 by Keiiti the physical processes needed instrumentation, the weakest record strong motions on film, Aki (SCEC director, 1991–1996) to successfully predict strong signals these instruments could which has to be retrieved and in an address when he was the motions, will lead to some record were just about at the then digitized. This is very time outgoing president of the Seis- increased understanding of the threshold of human detection. consuming. The advantage of mological Society of America. physics. Now, the digital accelerographs digital instruments is that the He said: “Our goal is to com- can record local earthquakes data are available immediately, pute seismic motion expected SCEC: Let’s focus on your work below magnitude 3, which is and the resolution is much at a specific site of an engi- as it relates to the Southern way below what a person can better. On analog, one can Vol. 5, No. 1, 1999 Southern California Earthquake Center Quarterly Newsletter 3 Professional resolve differences in accelera- has either better or worse Highlights tion of maybe 1,000th of the funding than many other fields acceleration of gravity. With of seismology. For instance, John Anderson new digital instruments, there’s most of our regional seismic about a 100-fold improvement. networks are seriously under- Education funded. Research on data Ph.D., geophysics, Columbia University B. S., physics, Michigan State University SCEC: How does that affect collected by those networks is your work? also under-funded. Professional SCEC Board of Directors University of Nevada, Reno–Mackay School of Mines JA: With a really strong earth- SCEC: Why? Professor of Geophysics, Department of Geological Sciences quake, you’re well above the Seismological Laboratory Director “noise” level over a certain JA: There is the usual cliché Research Interests frequency band; with digital answer: that without more John Anderson’s research in strong motion seismology has taken him to instruments, you are well above frequent disasters, the public Mexico, Japan, Turkey—and yes, even exotic southern California. He’s the noise level for a wider and Congress tend to forget hosted visiting scholars from India, Iran, China, and Korea, and looks forward to traveling to those places. His research interests span all as- range of frequencies. So you about earthquake hazards, and pects of engineering seismology, including applications of geological have much more accurate data seismology drops to a lower and seismological information to estimate seismicity and seismic haz- for both lower and higher priority on the political agenda. ards; recording strong ground motions; understanding the physics of frequencies than with the old That may contribute to the near-source ground motions; and applications to engineering problems. problem, but I don’t think it is Selected Publications the complete answer. Another Anderson, J. G., and S. Hough, A model for the shape of the Fourier Major earthquakes occur amplitude spectrum of acceleration at high frequencies: Bull.
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