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⊥
,
in relation to the
width of the asthenosphere uplift. The observation site is located at the epicentre of the uplift.
The uplift half-width
Fig. 8.25
The transverse and longitudinal apparent-resistivity curves
n
- locally normal
curves outside and over the asthenosphere uplift. For the model from Fig. 8.22 with param-
eters
v
=
5
,
25
,
50
,
100
,
250
,
500
,
750 km; ˙
n
,
n
and ¨
˙
n
,
¨
h
2
=
1
=
10 Ohm
·
m
,
h
1
=
1km
,
2
=
10000 Ohm
·
m
,
h
2
=
99 km
,
49 km
,
h
=
50 km
,
3
=
10 Ohm
·
m
⊥
=
,
=
⊥
,
tive ratios (
0
.
022
0
.
1). With widening the uplift, the curves
depart from the ˙
n
-curve and approach the ¨
n
-curve characterizing the uplift. At
-curve almost merges with the ¨
=
v
=
100 km, the
n
-curve (
2) and comes to
⊥
-curve remains close to ˙
the normalcy, while the
n
-curve and shows no evidence
⊥
=
⊥
-curve almost merges with the
of the uplift (
0
.
45). But at
v
=
500 km, the
⊥
=
¨
n
-curve and also comes to the normalcy (
2
.
24). Using these estimates, we can
-curves allow for the one-dimensional
say that in model under consideration the
⊥
-curves is
inversion if
≥
2, whereas the one-dimensional inversion of the
⊥
≥
justified if
5.
The next question is how the distortions of the apparent-resistivity curves
depend on the lithosphere resistivity. Figure 8.26 shows the curves in the model
from Fig. 8.22 with the lithosphere resistivity
2
÷
2
.
2
=
,
,
·
1000
10000
100000 Ohm
m
v
=
,
and
the
half-width
of
the
asthenosphere
uplift
100
250 km.
The
obser-
