Specifications

University of Pretoria etd – Combrinck, M (2006)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600

Distance [m]

Channels 1-13

Channels 14-27

Channels 1-13

EM Response (pV/Am )

Figure 5-19: EM Response over conductor.

5.3.2 Automated processing

The conductivity depth section was calculated according to the same procedures set out

in paragraph 5.2.3 and the conductor decay constants, half space decay behaviour and

sign-changes determined as described in Chapter 4. The results are shown in Figures 5-

20 to 5-23. The horizontal extent of the conductor is estimated to be from station

1700m to 2300m. The apparent extension of the conductor on either side can be

explained in the same way as diffraction hyperbola phenomena on seismic sections.

Stations not directly above the conductor will still measure its response, but data are

plotted directly below the stations where it was measured, resulting in side “tails” on the

conductivity depth sections. These effects are much more pronounced for dipping and

vertical bodies. In this case it can be distinguished clearly based on the hyperbolic nature

of the tail (station 2300m to 2800m), the corresponding drop in amplitude, and especially

the “decrease of depth with increase of time” behaviour manifested as the white space

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