Specifications

University of Pretoria etd – Combrinck, M (2006)
Repeat
for NumberOfChannels=4
to NumberOfChannels=(20-4)
YES
NO
Repeat
for beginChannel=0
to beginChannel=(20-NumberOfChannels)
Calculate least squares regression parameters:
m := slope
c := y-intercept
R := correlation coefficient
2
Calculate closest distance of m to either
-2.5 or -4
mError = minimum of
abs(m+2.5) AND abs(m+4.0)
Assign parameters to “best fit” combination and
set this distance to -2.5 or -4 as new
SpecifiedSlopeLimit.
combinationR =
2
R
SpecifiedSlopeLimit=mError
combinationBeginChannel=beginChannel
combinationNrOfChannels=NumerOfChannels
combinationSlope=m
combinationIntercept=c
2
Test whether calculated parameters fall
within user-specified (or default) limits.
if (R > SpecifiedRegressionLimit) AND
(mError < SpecifiedSlopeLimit)
2
Figure 4-2 Flow diagram for decay curve slope analysis.
Based on the decay curve analysis function every sounding is classified as exhibiting half
space behaviour, S-layer behaviour or neither of these.
4.3.2 Confined conductor behaviour
Analysing soundings for behaviour typical of confined conductors is done very similar to
the layered earth case. Once again, all stations and all channel combinations are analysed
with higher priority to more channels and later times. The main difference is that straight
line behaviour is now looked for in the semi-logarithmic environment, i.e. only the ∂B
z
/∂t
values are transformed to the logarithmic domain. Furthermore, there are no predefined
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