Fundamentals of Geophysical Data Processing, 2nd edn

Abstract

Book reviews 217 of the chapters discuss different aspects of this problem. D. Moos presents an interesting case study of VSP in fractured crystalline rock. The importance of both scattering and anelasticity is emphasized. M. Simaan and P. L. Love discuss the synthesis of VSP including the effects of absorption, dispersion and frequency-dependent reflection coefficients. E. Strick in a significant chapter occupying almost a third of the book provides a thorough review of anelasticity and P-wave distortion. In comparing well log sonic data and VSPs it is essential that dispersion and distortion are accounted for properly. In this excellent article, Strick considers the various mathematical models for attenuation and dispersion and compares the predicted waveforms with observations. It might be argued that too much emphasis is placed on analytic models. Mathematical methods and final results are often sensitive to analytic details not necessarily required by the data nor predicted by physics. Perhaps a more general, numerical approach would be preferable and more flexible as available data expand. Nevertheless, this article is to be highly recommended.Three chapters in the book consider synthetic VSP data. The article by Simaan and Love in which the normal recursive transfer model is used connecting up-and downgoing wave in successive layers, has already been mentioned. J. M. Mendel extends this method using the so-called 'state variable' models. The Bremmer series decomposition is used to separate primaries and multiple seismograms. These two chapters are restricted to plane wave seismograms. In the other chapter on modelling, D. Khosla and G . H. F. Gardner use both scale laboratory models and finite difference solutions to model realistic structures. Unfortunately, the book contains no mention of modelling techniques intermediate between plane wave and finite difference methods. The final chapter of the book by E. R. Kanasewich, D. Bingham and C. Gold is outside the main scope of the book as its title suggests: 'Continuous monitoringof rnicrotremors using a digital seismic nrray'. mis book natLlraily suffers fronl the rapid growth of its subject. The main emphasis is on near-offset VSP data while many recent developments have been with far-offset and hole-tohole tomography. Most seismologists will be happy to use library copies of this book rather than buy their own. Nevertheless, much is useful as introductory reading for VSP techniques and the chapter by E. Strick is highly recommended. Scientific Publications, OxJi,rd, I985 274 pp., .~ 242.00The interpretative techniques that are being used in the seismic exploration industry have changed considerably in the past, and continue t o d o so a t present. A major breakthrough occurred around 1970 when Claerbout introduced wavc equation migration with finite difference met.hods, soon to he followed by Kirchhoff summation and a variety of methods,

The One-Way Wave Equation: A Full-Waveform Tool for Modeling Seismic Body Wave Phenomena

“…With improvements in data quantity and quality, improved waveform simulation using algorithms based on physically-motivated approximations that describe the frequency-dependent effects of wave propagation are becoming increasingly important [75; 76]. For instance, in the pioneering study of [77], the acoustic parabolic equation of [78] was adapted to study the P-wave traveltime and amplitude anomalies over the NORSAR array. Their results indicated that the 3D heterogeneities in the underlying lithosphere/asthenosphere could be modeled, that the observed large scale traveltime and amplitude anomalies across the array share the same structural origin, and that the teleseismic P-waves are deflected no more than 5 • from the propagation path.…”

Efficient minimum-phase prefilter computation using fast QL-factorization

“…A classical way of obtaining the minimum-phase filter, H min , is by using the root method of spectral factorization, where we first find roots in the polynomial given in (3), and reflect the roots located outside the unit circle, into the circle, [1], [3]. Based on the roots inside and on the unit circle, a new polynomial can be computed in the z-domain, which represents the minimum-phase filter.…”

Forward propagation of acoustic pressure pulses in 3D soft biological tissue

“…Wide-angle parabolic approximations are also available. These are frequently used in underwater acoustics and geophysical applications, and lead to higher-order partial differential equations Claerbout (1976). They do not, however, appear that frequently in ultrasonic imaging, where the 15°a pproximation is thought to be adequate.…”