Information Technology Reference
In-Depth Information
ReW
zy
ImW
zy
W
zy
0.1
0.05
0
10000 s
-0.05
-0.1
y, km
-1500 -1000 -500
0
500
1000
1500
0.15
0.1
0.05
0
1000 s
-0.05
-0.1
-0.15
y, km
-1500 -1000 -500
0
500
1000
1500
0.1
0.05
0
100 s
-0.05
-0.1
y, km
-1500 -1000 -500
0
500
1000
1500
Fig.
8.27
The
W
zy
-
profiles
passing
across
the
regional
asthenosphere
uplift
(
v
=
250 km).
For
the
model
from
Fig.
8.22
with
parameters
1
=
10 Ohm
·
m
,
h
1
=
1km,
h
2
=
2
=
10000 Ohm
·
m
,
h
2
=
99 km
,
49 km
,
h
=
50 km
,
3
=
10 Ohm
·
m
.
Period
T
=
100
,
1000
,
10000 s
-curves measured at the epicentre of the uplift are slightly
distorted and allow for one-dimensional interpretation.
The
W
zy
-profiles are shown in Fig. 8.27. In the period range from 100 s to
10000 s the real tippers Re
W
zy
do not change their sign with frequency, while the
imaginary tippers Im
W
zy
do change. Note that Re
W
zy
and Im
W
zy
are of the same
sign on high frequencies (
T
twice its depth, the
=
1000-10000 s). The minima and maxima of Re
W
zy
and Im
W
zy
are observed over the
left and right edges of the asthenosphere uplift. It is evident that at all frequencies
under consideration the real induction arrows point away from the uplift epicentre,
while the imaginary induction arrows reverse their direction in the transition from
the high frequencies to the low ones.
Figure 8.28 presents curves for Re
W
zy
and Im
W
zy
measured over the right edge
of the uplift with half-width
=
100 s) and of opposite sign on low frequencies (
T
m. It is seen
that narrowing the uplift from 500 km to 100 km and increasing its resistivity from
10 Ohm
v
=
50
,
250 km and
3
=
10
,
25
,
50 Ohm
·
·
·
m we substantially diminish the real and imaginary tippers,
but they still are measurable.
mto50Ohm
