Information Technology Reference
In-Depth Information
Fig. 7.25
Electromagnetic field profiles in the three-segment model with conductive central
segment shown in Fig. 7.16;
y
-distance to the centre of the model. Model parameters:
1
=
,
1
100 Ohm
·
m
,
h
1
=
1km
=
1Ohm
·
m
,v
=
10 km
,
2
=
10000 Ohm
·
m
,
h
2
=
99 km
,
3
=
0 Profile parameter: period
T
=
1
−
1000 s
conductance of underlying sedimentary strata. This galvanic effect is referred to as
the
screening or shielding effect.
A model of the galvanic-screening effect is shown in Fig. 7.27. Here the sed-
imentary strata consists of three layers: the upper conductive layer (
1
,
h
1
), the
highly resistive intermediate layer
2
>>
1
,
h
2
) and the lower inhomogeneous
