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Geoelectrical prospecting

Class at Faculty of Science |
MG452P43

Syllabus

1. Introduction - basic equations of EM field, types of EM fields, sources of geoelectrical fields, general measurement techniques, classification of geoelectrical methods.

2. Resistivity method - resistivity of rocks, basic theory of stationary electric field.

3. Resistivity sounding - direct problem, geoelectrical section, basic types of sounding curves, computation of theoretical curves, inverse problem, interpretation procedures.

4. Resistivity profiling - electrode arrays, direct problems, characteristic model curves, methodics of measurement, data processing, interpretation.

5. Multielectrode measurements - principle, methodics, application. Borehole variants of resistivity method - principles, modifications.

6. Magnetotelluric method - sources and character of MT field, EM induction in homogeneous halfspace, principle of MT sounding, sounding curves, interpretation.

7. VLF method - sources, signal propagation, origin of anomalies, elliptic polarization, inductive variant (methodics of measurement, characteristic curves, data processing, interpretation), VLF-R (principle, measurement, 2D inhomogeneities, two horizontal layers).

8. EM methods in frequency domain - quasistationary normal field of VMD and HED, principle of frequency sounding (far and near zone), EM profiling (principle, large source, moving source, conductivity meters).

9. Time domain EM methods - principle, origin of secondary field, normal field of loop and HED, near and far zone, transient sounding and profiling.

10. Georadar - principle of impulse georadar, central frequency, wave number, reflection, attenuation, wave length, methodics of measurement.

11. Self-potential method - natural electrochemical activity, origin of potentials, field measurements (potential, gradient), data processing, interpretation.

12. Induced polarization method - polarization of rocks, IP phenomenon, time domain IP (principle, measured parameters, methodics of measurement, interpretation), frequency domain IP ( amplitude-phase mesurements, spectral IP).

Annotation

Basic equations of EM field, classification of geoelectrical methods. Resistivity method (sou-nding, profiling), multielectrode measurements, borehole variants of resistivity method.

Mag-netotelluric method. Very low frequency method (inductive and resistivity variant).

EM me-thods in frequency domain. Time domain EM methods.

Georadar. Self-potential method.

Induced polarization method.