BOOK REVIEW

F. Mulargia and R.J. Geller (eds.), Earthquake Science and Seismic RiskReduction, NATO Science Series IV. Earth and Environmental Sciences, Vol.32, Kluwer Academic Publishers, Dordrecht, 2003, 338 pp., ISBN 1-4020-1777-4 (hardback), £104, ISBN 1-4020-1778-2 (paperback), £44.

What is ‘‘Earthquake Science’’? The second part of the title, ‘‘Seismic RiskReduction’’, points us in the direction of earthquake hazard assessment andpossibly earthquake prediction. This pointer is correct. There is more,however.

The book resulted from the NATO Advanced Research Workshop ‘‘Stateof Scientific Knowledge Regarding Earthquake Occurrence and Implicationsfor Public Policy’’ which took place in Italy from October 15th to October19th, 2000. So, is this another incoherent collection of papers which werepresented at that workshop? Definitely not. The editors correctly state ‘‘...[This book] is a uniformly edited collection of contributions by leadingauthorities, designed to provide a comprehensive one-volume summary ofthe state of the art in both the basic and applied aspects of earthquakeoccurrence and seismic risk reduction’’. The composition of authorship of thebooks’ chapters also speaks of the close integration and intense exchange, aswell as controversy, among the participants. A preface and a list of sevenrecommendations on how to scientifically and practically address seismichazard reduction precede eight chapters on diverse but coherent subjects.

The first chapter (Modeling earthquakes, by F. Mulargia and R.J. Geller,19 pp.) sets the stage by showing that even the most basic processes inearthquake physics are poorly understood. Examples given range from themechanism of an individual earthquake to the space-time dynamics ofearthquake populations. The proper use of statistical methods for modelbuilding is reviewed and deterministic, complex and stochastic models arecompared. It is noted that complex systems appear to be relevant forearthquakes. The chapter ends by recalling the possible definitions of anearthquake prediction or forecast and states the scientific consensus that it ispresently impossible to predict imminent individual large events.

Chapter two (The classical view of earthquakes, by S. Castellaro, G. DiToro, M. Ciccotti, Y.Y. Kagan, F. Mulargia, I. Main, 82 pp.) discussesearthquakes from the classical viewpoint of continuum mechanics, discrim-inating earthquake kinematics (‘‘slip on fault generating seismic waves’’) and

Surveys in Geophysics (2006) 27:383–386 � Springer 2006DOI: 10.1007/s10712-005-5417-9

earthquake dynamics (‘‘why and how these slips occur’’). Both aspects arereviewed and their problems summarized by first stating a geologist’s point ofview, then a seismologist’s. Laboratory experiments and their fundamentaldifferences to processes on the crustal scale are discussed next. The chapterends with the insight that classical models yield little understanding of thespace-time patterns of seismicity.

The third chapter (The physics of complex systems: applications toearthquakes, by F. Mulargia, I. Main, M. Ciccotti, S. Castellaro, J. Kertesz,46 pp.) starts with the seemingly radical statement that the classical theoryshould be replaced by an entirely new approach. The statement is motivatedby listing several basic features of earthquake population dynamics, such asclustering, which cannot be classically explained. Subsequently, concepts ofstatistical physics such as phase transitions, critical points and scale invari-ance are introduced. Models from percolation via cellular automata to sliderblocks lead to the discussion of self-organized criticality. Computational andfundamental problems pertaining to the new models are discussed. In con-clusion, it is stated that the complex systems approach greatly improvesunderstanding earthquake dynamics and allows the assessment of predict-ability. Indeed, only probabilistic forecasts will be possible.

Chapter four (Time-independent hazard, by D. Albarello, M. Mucciarelli,A.J. Michael, N. Field, A. Frankel, J. Gomberg and K. Shedlock, 33 pp.)starts the more applied part of the book. It deals with seismic hazardassessment and site effect evaluation, i.e., those procedures currently in use toproduce probabilistic seismic hazard assessment maps for long-term plan-ning. A special section discusses the estimation of time-independent earth-quake probabilities, a crucial ingredient needed for the estimation of hazard.

Chapter five (Time-dependent hazard estimates and forecasts, and theiruncertainties, by A.J. Michael, N. Field, A. Frankel, J. Gomberg, K. Shed-lock, Y.Y. Kagan, Y.F. Rong, D.D. Jackson, P.B. Stark, and D.A. Freed-man, 36 pp.) deals with the question whether the incorporation of some(statistical) model can yield better forecasts of seismicity than time-inde-pendent estimates. Two examples are discussed, the current approach by theUSGS to develop a physically based statistical distribution of earthquakerecurrence on a network of faults, and a data-driven approach based onrecent seismic activity. A contribution from the purely statistical point ofview concludes this chapter by saying that it is difficult to make sense ofearthquake probabilities, rendering them essentially useless. This chapter isnecessarily the most incomplete as several other earthquake predictionschemes currently under evaluation are not represented.

Chapter six (Gathering new data, by F. Rocca, F. Sanso, P.A. Pirazzoli,33 pp.) discusses satellite geodesy (INSAR) and paleoseismology of coast-lines as new sources of data that might help to answer questions not tractablewith either the classical or the complexity approach to earthquakes. INSAR,

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in particular, allows the observation of strain with high spatio-temporalresolution for the first time and might unveil the details of strain accumu-lation, propagation and release. First high resolution studies have alreadyshown that it is wrong to think of a single fault rupturing during a largeevent. Rather, many sub-events are involved. This should have been the placeto discuss that earthquakes are caused by stresses, not its observable proxystrain. Observing strain means observing non-linear threshold dynamicswhile the underlying stress evolution remains hidden. This further and fun-damentally impedes prediction.

Chapter seven (Seismic risk mitigation, by S.A. Anagnostopoulos,M. Erdik, E. Durukal, B. Siyahi, Y. Fahjan, K. Sesetyan, M. Demircioglu,H. Akman, 34 pp.) starts the third part of this book, which addresses issuesthat directly affect society. It presents two case studies in seismic riskreduction from Greece and Turkey. Seismic risk means the potential impactof earthquakes on humans and man-made structures so that, e.g., pre-paredness and building vulnerabilities are discussed here.

The last chapter (Earthquake Prediction and public policy, by R. B.Olshansky and R.J. Geller, 46 pp.) finally explains why earthquake predic-tion has become a sensitive subject (and probably why ‘‘prediction’’ does notappear in the title of the book). Namely, the subject is not purely of scientificinterest, but equally, or even more so, relates to public policy, not leastbecause of the strong media interest. Cranks as well as scientists can thuseasily receive extensive attention and cause societal as well as scientificdamage. A review of the history of earthquake prediction research and policyis followed by a discussion of the costs and benefits to society of a hypo-thetical short-term prediction. Next, the earthquake prediction policies of theU.S. and Japan are described in some detail. A section on public reactionslists several episodes of failed predictions and their common features. Thechapter concludes that emphasis should be on mitigation rather than onprediction but, as prediction (research) will continue, procedures need to setup to rigorously assess any claims of prediction. Furthermore, to stop thecontinuing loss of credibility, seismologists should not claim progresstowards deterministic earthquake prediction to secure funding.

This is a comprehensive and up-to-date book mainly on earthquakeprediction, in the practical sense of including policy issues as well as in thesense that ‘‘once we can predict something, we understand it’’. The physics ofcomplex systems, however, uses the concept of emergence to imply unpre-dictability of global features and predicts non-determinism of individualevents. Regrettably, the book contains no such discussion. It does, however,include the possibility of a ‘‘semi-empirical predictive power even without thecapability to physically model the earthquake source process’’. From a morepractical point of view it is somewhat surprising that the subject of earlywarning receives almost no attention.

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This book should be read by everybody interested in earthquake predic-tion and seismic hazard mitigation, expert or not, scientist or administrator.It may be read out of sequence and makes a good reference. Each chaptercontains a comprehensive set of references to recent literature. A CD-ROMwith color figures is included.

CHRISTIAN GOLTZ1 Christian-Albrechts-Universitat Kiel

Otto-Hahn Platz 1Kiel, Germany

University of CaliforniaDavisUSA

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