K P I / I T t i K A - REVIEWS ATTILAMESK6: D i g i t a l F i l t e r i n g : A p p l i c a t i o n s i n G e o p h y s i c a l E x p l o r a t i o n for Oil. Akademia Kiad6, Budapest 1984, 636 pp. This extensive monograph of Mesk6 clearly demonstrates the unusual development of methods of geophysical interpretation over the last two decades. Rapidly developing computer equipment provides new possibilities namely in effective processing of large data sets, which is typical for applied geophysics research. The geophysicists are thus offered the use of mathematical models of processing and intepretation which are capable of disclosing most effectively information about the object, the source of which is a set of measured (digitized) data. The book is divided into three parts, the first two of which form the mathematical (i.e. deterministic and stochastic) foundation of the applications, to which the third part is devoted; this dicision corresponds to the logical sequence of constructing the model of processing the dala sets. The first stage is the establishing of the deterministic theory by measuring the object involved; the subsequent stochastic model, respecting the fact that information is obtained by measuring, can only be correct under this condition. The final geophysical interpretation of the results of the processing, naturally, takes into account the possibilities of the method used. Part 1. Techniques of Digital Filtering and Deterministic Filters (340 pp.). This part contains the following sections: 1. Fourier and Hilbert transform; 2. Convolution and correlation; 3. Digital signals; 4. The discrete Fourier transform and the fast Fourier transform algorithm; 5. The z-transformation and recursive filters. Part 2. Fundamentals and Applications of Optimum Filters (129 pp.). This part contains the following sections: 1. Groundwork (A short summary of probability theory and Review of statistics); 2. Stochastic processes; 3. Digital Wiener filters; 4. Optimum filters for signal-to-noise ratio enhancement. The advantage of both these parts is the manner in which the relatively demanding subject of a distinctly mathematical nature is presented. The author adopted the descriptive approach which is clear, concise and illustrative. He makes abundant use of graphical representations and well-arranged tables, into which be has summarized the acquired knowledge. A great advantage is also that the numdrical examples, which serve to elucidate the mathematical terms he introduces, are related to problems of geophysical interpretation; this will immediately indicate their usefulness to the reader. The mathematical part is the work of an experimenced pedagogue of long standing. Part 3, called Some Applications in the Seismic, Gravity and Magnetic Prospecting Methods, reflects the long years of experience of the author as consultant to the Geophysical Prospecting Company. This part (138 pp.) has numerous figures and represents a clear-cut documentation of the part played by improved mathematical models in the process of objectivization of geophysical interpretations, demonstrating that the use of innovational procedures in applied geophysics is useful. Ludmila Kubd~kovd

D. JUSTIN SCHOVE:S u n s p o t Cycles. B e n c h m a r k P a p e r s i n G e o l o g y Vol. 68. Hutchinson Ross Publ. Comp. Stroudsburg, Pennsylvania 1983. The book contains 40 papers, already published earlier, by 21 authors (the author of 19 of them is D. J. Schove) concerning solar activity cycles and their manifestations on Earth. Considerable attention is devoted namely to the prolongation of observation series of sunspots and aurorae into the pats, to the relations between solar cycles and the climate, also using geological research. The reprinted papers are divided into 7 parts, the titles of which illustrate the contents of the book best: I. Early sunspots; II. The eleven-year cycle; III. Early aurorae; IV. Synthesis; V. Longer cycles; VI. Suspots in history and their effect on climate; VII. Varve and geological cycles. Each of these parts is introduced by the editor's comments with numerous references to Studia geoph, et geod. 29 [1985]

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Revie~s literature. Numerous graphs and tables concerning the problems involved, which can be useful for further research in this field, are included in the Introduction and Appendices. The book compiled by D. J. Schove is interesting to all who are concerned with the physics of solar-terrestrial relationships and is welcome particularly at this time when the I C S U is preparing the important international program "Geosphere Biosphere -- Global Change", whose problems are closely related to those in D. J. Schove's "Sunspot Cycles".

Miloslav Kopeek~

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