xii CONTENTS 



CHAPTER FAOK 



9. Seismic Methods (Cont.) 



F. Photographic Recording; Time Marking 614 



G. Calibration of Seismographs 615 



10. Electrical Methods 619 



I. Introduction 619 



A. Fundamentals 619 



B. Classification of Electrical Methods 624 



II. Electrical Properties of Rocks 628 



A. Electrochemical Properties 628 



B. Metallic and Electrolytic Current Conduction 632 



C. Dielectric Current Conduction 640 



D. The Effects of Magnetic Permeability 642 



E. Methods for the Determination of Rock Resistivity 642 



F. Methods for the Determination of Dielectric Constants 649 



G. Resistivities' and Dielectric Constants of Minerals, Ores, Rocks, 



and Formations 656 



III. Self-Potential Method 667 



A. General 667 



B. Equipment; Electrodes; Surveying Procedure 669 



C. Interpretation 671 



D. Corrections 675 



E. Results 675 



IV. Equipotential-Line and Potential-Profile Methods 681 



A. Conditions in Stationary Fields 681 



B. Conditions for A.C. Fields 685 



C. Field Procedure ; Equipment 692 



D. Interpretation 697 



E. Discussion of Results 703 



V. Resistivity Methods 707 



A. General 707 



B. Electrode Arrangements 709 



C. Potential Functions for Layered Media 711 



D. Procedure; Equipment 723 



E. Interpretation 727 



F. Results Obtained by Resistivitj'^ Surveying 735 



G. Electrical Logging 744 



VI. Potential-Drop-Ratio Methods 744 



A. General 744 



B. Theory 745 



C. Equipment; Procedure 752 



D. Results , . 755 



VII. Electrical Transient ("Eltran") Methods . 757 



VIII. Electromagnetic Methods 763 



A. Electromagnetic Methods with Galvanic Power Svipply 764 



B. Electromagnetic Methods with Inductive Power Supply 773 



IX. Radio Methods 809 



A. General 809 



B. Transmission Measurements 812 



C. Field-Strength Measurements 815 



