CONTENTS 



Page 



Preface to Second Edition v 



Contributors and Collaborators, Second Edition vi 



Preface and Acknowledgments, First Edition ix 



CHAPTER I 

 Introduction 1 



History of development ; magnetic methods ; gravitational methods ; electrical 

 methods ; seismic methods. Contemporary workers and present developments. 

 Trends in development of future methods. 



CHAPTER n 

 Geologic and Economic Background of Exploration Geophysics 19 



Introduction; general factors governing application and choice of geophysical 

 methods ; classification and scientific basis of geophysical methods ; technique 

 of applying a geophysical method. Geophysical methods in prospecting for 

 petroleum ; general field of application ; relative utility and importance of the 

 methods; choice of methods for particular geologic problems; economics of 

 petroleum geophysics ; operating crew costs. Geophysical methods in mining ; 

 general field of application ; choice of methods for particular geologic prob- 

 lems. Geophysical methods in water supply engineering; choice of methods. 

 Geophysical methods in civil engineering ; examination and location of dam 

 sites ; location of reservoir sites ; highway engineering. 



CHAPTER III 

 Magnetic Methods 61 



Physical concepts ; classification of magnets and substances ; law of force ; unit 

 field strength and magnetic fields ; permeability and susceptibility ; field 

 strength, Gauss positions. Terrestrial magnetism ; declination ; inclination ; 

 dip ; magnetic gradients ; distribution of earth's magnetic field ; latitude and 

 longitude corrections ; time variations ; magnetic instruments. Field procedure, 

 interpretation ; susceptibility of rocks and minerals ; classification of anoma- 

 lies ; examples of field work. The mobile magnetometer ; airplane, helicopter, 

 and ship-borne operations. Examples of aerial magnetic mapping. Patents. 



CHAPTER IV 

 Gravitational Methods 247 



Fundamental principles and phenomena ; gravitational constant and weight of 

 the earth. Factors causing variations in gravity ; Bouguer correction ; 

 isostasy. Density of materials. Quantities measured in gravity prospecting. 

 Absolute gravity measurements ; the pendulum. Relative gravity measure- 

 ments ; the torsion balance. Equipotential surfaces. Theory of interpretation ; 

 torsion balance equipment ; field measurements ; topographic corrections ; 

 leveling ; computations ; general rules of interpretation ; gravity contours ; 

 examples of field work. The gravity meter ; design and operating principles ; 

 land and underwater meters ; diving bell. Calibration of meters. Leveling and 

 photogrammetric mapping. Field operations ; drift curve and closure ; latitude 

 and terrain corrections. Field calculations and necessary corrections. Exam- 

 ples of field work. Patents. 



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