WOODS 

 HOLE, 

 CONTENTS \ MASS. 



PART I 



CHAPTER PAGE 



1. Introduction 3 



I. Significance of Geophysical Exploration 3 



II. Geophysics as a Tool for Determining Geologic Structure; Excep- 

 tions; Indirect Mineral Location 4 



III. Major Fields of Geophysical Exploration 5 



2. Methods of Geophysical Exploration 7 



I. Classification 7 



II. Gravity Methods 9 



III. Magnetic Methods 16 



IV. Seismic Methods 19 



V. Electrical Methods 25 



VI. Geophysical Well Testing 33 



VII. Miscellaneous Geophysical Methods 35 



3. Measurement Procedures in Geophysical Exploration 38 



I. Significance and Measurement of Physical Quantities Involved — 38 

 II. Arrangement of Observation Points with Relation to Geologic 



Objects 41 



4. Geophysical Methods in Oil Exploration 43 



5. Geophysical Methods in Mining 49 



I. Metal Mining 49 



II. Mining of Nonmetallics 52 



A. Coal, Including Anthracite and Lignite 53 



B. Sulfur 53 



C. Salt 54 



D. Nitrates, Phosphates, Potash 54 



E. Building and Road Materials 54 



F. Abrasives 55 



G. Materials for Various Industrial Uses 55 



H. Gems and Precious Stones 56 



6. Applications of Geophysics in Engineering 57 



I. Geological Applications 57 



A. Foundation Problems 57 



B. Location of Construction Materials 60 



C. Location of Water 60 



II. Nongeological Applications 62 



A. Dynamic Vibration Tests of Structures 62 



B. Strain Gauging 62 



ix 



