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1
2
S 1 /
S 1 )
xy = 1
S 1 ) 2
f ( y
,
S
h
S 1 /
xy =
+
+
f ( y
,
S 1 /
S 1 )
2
+
f ( y
,
1
2
S 1 /
S 1 )
= 1
S 1 ) 2
f ( y
,
S
yx
h
yx
S 1 /
=
+
+
f ( y
,
.
S 1 /
S 1 )
2
+
f ( y
,
Letting S 1 < S 1 , it is easy to show that
xy
xy
yx < 1
yx < 1. So,
>
1
,
>
1 and
,
xy >
xy > yx . These relations are characteristic of the lateral
flow-around effect observed in the vicinity of a resistive inclusion where zones of the
current concentration and deconcentration appear (Fig. 7.32). In the concentration
zones the apparent resistivities increase, while in the deconcentration zones they
decrease.
Letting S 1
n ,
˙
yx < ˙
n and
>
S 1 ,wehave
xy < 1
,
xy < 1 and
yx
>
,
yx
>
xy < ˙
n ,
1
1. So,
yx
yx . These relations are characteristic of the lateral current-
gathering effect observed in the vicinity of a conductive inclusion. Zones of the cur-
rent concentration and deconcentration, in which the apparent resistivities increase
and decrease, are displayed in Fig. 7.33.
Figure 7.34 presents the apparent-resistivity curves,
>
n and
xy <
˙
yx , distorted by the
flow-around and current-gathering effects. The observation site x
xy and
=
0
,
y
=
1
.
5b
is located outside a resistive ( S 1 /
S 1 =
16) or conductive ( S 1 /
S 1 =
1
/
16) inclusion.
A / 1
The
A
curves are plotted in the log-log scale with ordinates
and abscissas
λ 1 /
λ 1
1 . The curves of
h 1 , where
is the wavelength in the medium of resistivity
xy and
yx are similar in form. They replicate the bell-type normal curve of ˙
n ,but
Fig. 7.32 Flow-around effect
in the vicinity of a resistive
inclusion
 
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