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In-Depth Information
Fig. 7.6
The Green function
in the Tikhonov-Dmitriev
model, the TM-mode;
model parameters:
h
2
/
h
1
=
,
2
/
1
=
49
,
,
3
=
100
1000
0; curve
parameter:
λ
1
/
h
1
⎧
⎨
⎩
1
S
1
(
y
)
=
Z
n
in the
S
1
-interval
S
1
S
1
(
y
)
Z
N
=
Z
⊥
(
y
)
=
(7
.
23)
S
1
S
1
(
y
)
o
h
S
1
S
1
(
y
)
Z
n
−
i
=
in the
h
-interval
.
In such approximation the transverse impedance
Z
⊥
(
y
) is defined as the product
of the normal impedance
Z
N
by the frequency-independent real factor
S
1
/
S
1
(
y
). In
the
S
1
-interval the transverse impedance
Z
⊥
(
y
) coincides with the locally normal
impedance
Z
n
(
y
)
=
1
/
S
1
(
y
)
.
But in the
h
-interval it differs from
Z
n
(
y
)
=−
i
o
h
The low-frequency values of
Z
⊥
(
y
) reflect
by the factor proportional to 1
/
S
1
(
y
)
.
variations in
S
1
(
y
)
.
They are statically distorted. This galvanic distortion was given
the title
S
-
effect
.
The
S
-effect manifests itself in the vertical
static shift
of the low-frequency
descending branch of the transverse apparent resistivity curve. According to (7.23),
Z
⊥
(
y
)
S
1
S
1
(
y
)
2
2
⊥
(
y
)
=
=
N
=
o
