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T o d i st a nt
e le c tr o d e
(N )
To distant
electrode (
Current
electrode
Potential
electrode
To distant
electrode (
A
)
N
)
V
X B M
B
M
T o d is ta n t
e l ec t ro d e
( A )
I
M
B
Z
Pole-pole
Z = X BM
b)
n . X MN
X MN
Potential
electrodes
To distant
electrode (
Current
electrode
X M N
A
)
n .X M N
V
B
M
N
N
T o d i st a n t
e le c tr o d e
( A )
I
M
45°
45°
45°
Z
B
Alternative
plotting point
Pole-dipole
Z = X MN ( n +1/2)
2
c)
X AB
n . X MN
X MN
X MN
Current
electrodes
Potential
electrodes
n . X M N
V
AB
M
N
X A B
N
M
45°
45°
I
B
Z
A
Dipole-dipole
Z = X MN ( n +1)
2
d)
X AB
X MN
X MN
X MN
X AB = 3 X M N
Current electrodes
X MN
X M N
Potential electrodes
X M N
I
A
M
N
B
V
B
N
M
A
Wenner
Z
Z = X AB /3= X MN
e)
X AB
X MN
X AB
Current electrodes
Off-centre
poten tial elec trodes
X MN
I
B
Potential electrodes
V
A
M
N
B
N
M
45°
45°
A
x
Schlumberger
Z
X A B
y
Alternative
plotting point
(off-centre potential
electrodes)
X M N
B
I
V
L
N
Z = X AB /2
A
x
M
Gradient
Figure 5.40 The commonly used electrode arrays and plotting conventions for soundings and pseudosections: (a) pole - pole, (b) pole - dipole,
(c) dipole - dipole, (d) Wenner, (e) Schlumberger and gradient arrays.
 
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