Thursday, August 13, 2015

Book Review: Treatise on Geophysics 2nd Edition

As a sitting SEG President I have to be somewhat selective accepting new commitments. You might think a book review is the last thing I would step into, after all I am barely keeping up a few Seismos columns per year in the Leading Edge.

But this is no ordinary book. Treatise on Geophysics 2nd Edition (TOG2) is an 11 volume tour de force, a broad and sprawling effort to capture the current state of knowledge in geophysics. From the outset that presents a problem. Geophysics is a vast collection of disciplines, specialties, topics, methods and so on. The full scope of geophysics cannot be captured even in 11 thick volumes (length varies from 907 page volume 1 to 302 page volume 9). But it is a majestic undertaking, well worth the effort. To paraphrase Robert A. Heinlein, such a book stitches the patches of the universe together into one garment for us.

The general scope of this laudable Elsevier project can be gathered from the volume titles: (1) Deep Earth Seismology, (2) Mineral Physics, (3) Geodesy, (4) Earthquake Seismology, (5) Geomagnetism, (6) Crustal and Lithosphere Dynamics, (7) Mantle Dynamics, (8) Core Dynamics, (9) Evolution of the Earth, (10) Physics of Terrestrial Planets and Moons, (11) Resources in the Near-Surface Earth.

How does one approach reviewing an 11-volume book? Based on education, I feel qualified to comment on volumes 1, 4, 5, 8 and 10. My entire working life, however, is within the scope of just volume 11.The last individual that is thought to known all of science was either Thomas Young (d. 1839) or Hermann Von Helmholtz (d. 1894), depending which historian you believe.  If we narrow the discussion to just geophysics, someone likely understood it all in the early 1960's (who?), before the subsequent explosion of applied science. It is the nature of a composite science like modern geophysics, that no one person can possibly be an expert in all aspects of the subject.

But that is precisely why magnificent projects like TOG2 are undertaken with an army of editors and contributors. The editor-in-chief of TOG2 is Gerald Schubert of UCLA, member of the National Academy of Sciences and famous as co-author with Donald Turcotte of the standard textbook Geodynamics. Each volume has one or two editors and individual chapters have one or more authors, so TOG2 runs the risk of being science by committee or, worse yet, a tired compilation of previously published papers presented as chapters. Yet, TOG2 compulsively and completely fights this temptation, creating instead a masterful collection of chapters by first-class authors rewarding the reader with a stroll right up to the dizzying height of current knowledge in literally hundreds of subject areas. In volume 1 alone, the list of chapter authors reads like a who's who, even if you are not in the field of Deep Earth Seismology: Dziewonski, Virieux, Cormier, Tromp, Levander, Zelt, Symes and Keller to name a subjective few.

The typical SEG reader will notice that TOG2 is not intended to span the applied geophysical subjects associated with fossil fuel and mineral exploration, although volume 11 (Resources in the Near-Surface Earth) is a good, self-contained overview. Rather, it deals with the fundamental science behind applied geophysics (particularly seismology) and its application to understanding the earth and planets. To give one example, Theory and Observations: Forward Modeling: Synthetic Body Wave Seismograms (vol. 1, ch. 6) is a panoramic discussion of seismic modeling algorithms, parameterization, and a broad view of heterogeneity, attenuation and anisotropy. One can easily forgive two colons in the chapter title considering the authoritative depth and breadth of the text. A picky reader might notice that constant Q theory is given as an approximation (that violates causality) without reference to the exact theory of Kjartansson, and anisotropy without mention of Thomsen. The former omission is particularly curious since Kjartansson's work appeared the prestigious  Journal of Geophysical Research. But these are quibbles that detract nothing from a strong authoritative text.

In my opinion, Treatise on Geophysics 2nd Edition is a splendid, ambitious encyclopedia of the fundamental geophysical sciences. As such, it would be a welcome addition to any working library in pure or applied geophysics. It's publisher, editors and authors are to be commended for undertaking and so finely executing such a task. One wishes that the major applied scientific societies (SEG, AAPG, SPE) would collaborate on a similar scale to create a treatise that would as adequately capture the current knowledge of applied geophysics.

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