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In-Depth Information
Table 11.1
Standard apparent resistivities
st
,
Ohm
·
m
28000
10000
3500
1600
700
260
120
52
√
T
,
s
1/2
1
2
5
10
20
50
100
200
the
xy
-curve including its bowl-type and bell-type elements is shifted upward to
fit the
st
-curve. Then the intact and shifted parts of the
xy
-curve are smoothly
interpolated.
Unfortunately, this attractive method should be applied with some reservation.
The most reliable results can be obtained in stable geological provinces (or at least
far away from anomalous zones such as rifts, subductions, plumes, volcanoes) where
the mantle's conductivity at depth of about 300-500 km hardly experiences gross
changes in horizontal directions. Note also that the distortions of low-frequency
Fig. 11.29
Static-shift
correction using the standard
apparent-resistivity curve
st
as a reference
