By A. A. R. Zhody, G. P. Eaton, and D. R. Mabey
Abstract
Introduction
Design of geophysical surveys
Collection and reduction of geophysical data
Interpretation
The literature of exploration geophysics
Electrical methods, by A. A. R. Zohdy
Telluric current method
Magneto-telluric method
Spontaneous polarization and streaming potentials
Direct current-resistivity method
Definition and units of resistivity
Rock resistivities
Principles of the resistivity method
Electrode configuration
Wenner array
Lee-partitioning array
Schlumberger array
Dipole-dipole arrays
Electrical sounding and horizontal profiling
Comparison of Wenner, Schlumberger, and dipole-dipole measurements
Problem of defining probing depth
Advantages of using logarithmic coordinates
Geoelectric parameters
Types of electrical sounding curves over horizontally stratified media
Electrical sounding over laterally inhomogeneous media
Limitations of the resistivity method
Analysis of electrical sounding curves
Qualitative interpretation
Determination and use of total transverse resistance, T, from sounding curves
Determination of total longitudinal conductance, S, from sounding curves
Determination of average longitudinal resistivity, pL, from a sounding curve
Distortion of sounding curves by extraneous influences
Quantitative interpretation
Analytical methods of interpretation
Two-layer interpretation
Three-layer interpretation
Four-layer (or more) interpretation
Empirical and semi-empirical methods of interpretation
Moore´s cumulative resistivity method
Barnes´ layer method
Applications of resistivity surveys in ground-water studies
Mapping buried stream channels
Geothermal studies
Mapping fresh-salt water interfaces
Mapping the water table
Mapping clay layers
Electromagnetic methods
Induced polarization methods
Relationship between apparent chargeability and apparent resistivity
Induced polarization sounding and profiling
Applications of induced polarization in ground-water surveys
References cited
Seismology, by G. P. Eaton
Elementary principles
Reflection versus refraction shooting
Comparison of the refleotion and refraction seismic methods in practice
Seismic refraction measurement in hydrogeology
Effect of departures from the simple stratified model
The multilayered model
Effect of a regular increase of velocity with depth
Effect of dipping layer
Effect of a sloping ground surface
Effect of a buried steplike re-fractor
Effect of a discordant steep sided body
Effect of a thin refractor
Effect of a velocity inversion at depth
Effect of a refractor of irregular conflguration
Effect of lateral varying velocities
Corrections applied to seismic refraction measurements
Elevation correction
Weathered-layer correction
Errors in seismic refraction measure ments
Application of seismic refraction measurements in hydrogeology
Mapping buried channels
Measuring depths to the water table
Determining the groee stratigraphy of an aquifer
Mapping lateral facies variations in an aquifer
Estimating porosity from seismic wave-velocity values
References cited
Gravimetry, by G. P. Eaton
Reduction of gravity data
Latitude correction
Tidal correction
Altitude corrections
Free-air correction
Bouguer correction
Terrain correction
Drift correction
Regional gradient
Bouguer anomaly
Interpretation of gravity data
Ambiguity
Interpretation techniques
Significance and use of density meaeurements
Application of gravimetry to hydrogeology
Aquifer geometry
Estimating average total porosity Surface method
Borehole method
Effect of ground-water levels on gravity readings
References cited
Magnetic methods, by D. R. Mabey
Magnetic surveys
Magnetic properties
Design of magnetic surveys
Data reduction
Interpretation of magnetic data
Examples of magnetic surveys
Gem Valley, Idaho
Antelope Valley, California
References cited
Cost of geophysical surveys in 1970
Electrical methods
Gravity surveys
Seismic surveys
Magnetic surveys
| AccessibilityFOIAPrivacyPolicies and Notices | |
| |
|