Introduction to the resistivity surveying method. The resistivity of ...

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List of Figures
Figure
Page Number
1. A conventional four electrode array to measure the subsurface resistivity. 1
2. Common arrays used in resistivity surveys and their geometric factors. 2
3. The three different models used in the interpretation of resistivity
measurements. 3
4. A typical 1-D model used in the interpretation of resistivity sounding
data for the Wenner array. 4
5. The arrangement of electrodes for a 2-D electrical survey and the
sequence of measurements used to build up a pseudosection. 6
6. The use of the roll-along method to extend the area covered by a survey. 7
7. The apparent resistivity pseudosections from 2-D imaging surveys
with different arrays over a rectangular block. 9
8. The sensitivity patterns for the (a) Wenner (b) Wenner-Schlumberger
and (c) dipole-dipole arrays. 12
9. Two different arrangements for a dipole-dipole array measurement
with the same array length but with different “a” and “n” factors
resulting in very different signal strengths. 14
10. A comparison of the electrode arrangement and pseudosection data
pattern for the Wenner and Wenner-Schlumberger arrays. 16
11. The sensitivity pattern for the pole-pole array. 16
12. The forward and reverse pole-dipole arrays. 17
13. Example of inversion results using the smoothness-constrain and
robust inversion model constrains. 21
14. An example of a field data set with a few bad data points. 22
15. Subdivision of the subsurface into rectangular blocks to interpret the
data from a 2-D imaging survey using different algorithms. 24
16. (a) The apparent resistivity pseudosection for the Grundfor Line 2 survey
with (b) the interpretation model section. 25
17. The observed apparent resistivity pseudosection for the Odarslov dyke
survey together with an inversion model. 26
18. The observed apparent resistivity pseudosection for the Sting Cave
survey together with an inversion model. 26
19. (a) The apparent resistivity pseudosection for a survey across a landslide
in Cangkat Jering and (b) the interpretation model for the subsurface. 28
20. (a) The apparent resistivity pseudosection from a survey over a derelict
industrial site, and the (b) computer model for the subsurface. 28
21. (a) Apparent resistivity pseudosection for the survey to map holes in
the lower clay layer. (b) Inversion model and (c) sensitivity values of
model blocks used by the inversion program. 29
22. Magusi River ore body. (a) Apparent resistivity pseudosection, (b)
resistivity model section, (c) apparent metal factor pseudosection and
(d) metal factor model section. 30
23. (a) The measured apparent resistivity pseudosection, (b) the calculated
apparent resistivity pseudosection for the (c) model section from an
underwater marine survey. 31
24. (a) The apparent resistivity and (b) inversion model sections from the
survey conducted at the beginning of the Birmingham infiltration study. 33
Copyright (1999-2001) M.H.Loke