Developments In Geophysical Exploration Methods 4

Geophysical prospecting is an applied science and the range of scientific principles to be applied is very wide. In this collection of original papers, the application of many different principles is described in the search for sulphides, other metallic ores and radioactive deposits. The papers are all concerned with surface observations and cover both the theory and the practice of the methods used. In all cases the advan tages and disadvantages of the methods are described and their role in the detection of mineral deposits is discussed and placed in context. Electromagnetic methods are covered in detail, involving the use of both electric and magnetic field effects. Techniques are described involv ing observations both at a number of discrete frequencies and with continuously changing frequency. In spite of the diversity of method it is interesting to note the strong links between the papers; two chapters, for example, start from the same fundamental illustration, first published by Won, of the basic relationship between source frequency, ground con ductivity and depth of penetration. The all-important economic aspects are not forgotten and the first chapter assesses the statistics of performance and describes their use in the shaping and management of an exploration programme. The editor takes this opportunity to thank the busy men who have set aside time to write these contributions.

Geophysical prospecting is an applied science and the range of scientific principles to be applied is very wide. In this collection of original papers, the application of many different principles is described in the search for sulphides, other metallic ores and radioactive deposits. The papers are all concerned with surface observations and cover both the theory and the practice of the methods used. In all cases the advan tages and disadvantages of the methods are described and their role in the detection of mineral deposits is discussed and placed in context. Electromagnetic methods are covered in detail, involving the use of both electric and magnetic field effects. Techniques are described involv ing observations both at a number of discrete frequencies and with continuously changing frequency. In spite of the diversity of method it is interesting to note the strong links between the papers; two chapters, for example, start from the same fundamental illustration, first published by Won, of the basic relationship between source frequency, ground con ductivity and depth of penetration. The all-important economic aspects are not forgotten and the first chapter assesses the statistics of performance and describes their use in the shaping and management of an exploration programme. The editor takes this opportunity to thank the busy men who have set aside time to write these contributions.

"The first phase of geophysical exploration is carried out on the subsurface.The subsurface in this phase is inaccessible to direct observation. D.W. Strangway presents an interesting and effective method: audiofrequency magnetotelluric (AMT) sounding. In the second phase where observations can be made, D.J Buchanan writes of fault detection in coal seams, and A. Hussain writes about of gravity surveys.Other contributions include, improvement of geophysical logs by filtering and a troublesome problem which can appear in either phase of exploration-discovery and exploration of caves and abandoned mine workings.'

Geophysical prospecting is an applied science and the range of scientific principles to be applied is very wide. In this collection of original papers, the application of many different principles is described in the search for sulphides, other metallic ores and radioactive deposits. The papers are all concerned with surface observations and cover both the theory and the practice of the methods used. In all cases the advan tages and disadvantages of the methods are described and their role in the detection of mineral deposits is discussed and placed in context. Electromagnetic methods are covered in detail, involving the use of both electric and magnetic field effects. Techniques are described involv ing observations both at a number of discrete frequencies and with continuously changing frequency. In spite of the diversity of method it is interesting to note the strong links between the papers; two chapters, for example, start from the same fundamental illustration, first published by Won, of the basic relationship between source frequency, ground con ductivity and depth of penetration. The all-important economic aspects are not forgotten and the first chapter assesses the statistics of performance and describes their use in the shaping and management of an exploration programme. The editor takes this opportunity to thank the busy men who have set aside time to write these contributions.

This new edition of the well-established Kearey and Brooks text is fully updated to reflect the important developments in geophysical methods since the production of the previous edition. The broad scope of previous editions is maintained, with even greater clarity of explanations from the revised text and extensively revised figures. Each of the major geophysical methods is treated systematically developing the theory behind the method and detailing the instrumentation, field data acquisition techniques, data processing and interpretation methods. The practical application of each method to such diverse exploration applications as petroleum, groundwater, engineering, environmental and forensic is shown by case histories. The mathematics required in order to understand the text is purposely kept to a minimum, so the book is suitable for courses taken in geophysics by all undergraduate students. It will also be of use to postgraduate students who might wish to include geophysics in their studies and to all professional geologists who wish to discover the breadth of the subject in connection with their own work.

An up-to-date overview of global optimization methods used to formulate and interpret geophysical observations, for researchers, graduate students and professionals.

One of the themes in current geophysical development is the bringing together of the results of observations made on the surface and those made in the subsurface. Several benefits result from this association. The detailed geological knowledge obtained in the subsurface can be extrapolated for short distances with more confidence when the geologi cal detail has been related to well-integrated subsurface and surface geophysical data. This is of value when assessing the characteristics of a partially developed petroleum reservoir. Interpretation of geophysical data is generally improved by the experience of seeing the surface and subsurface geophysical expression of a known geological configuration. On the theoretical side, the understanding of the geophysical processes themselves is furthered by the study of the phenomena in depth. As an example, the study of the progress of seismic wave trains downwards and upwards within the earth has proved most instructive. This set of original papers deals with some of the more vigorous developments in subsurface geophysics: and it is hoped that it will contribute to the understanding of geophysical phenomena in the solid. The editor thanks the busy workers in the several fields who have made time to produce these contributions.