Fróðskaparrit - 01.01.1982, Page 43

Some Magnetotelluric Measurements on the Faeroe Islands 51
and E-W direction exists with increased period. For the N-S
direction we observe a minimum at 100 secs which is likely
to represent a low resistivity structure.
The Bostick inversion is shown in fig. 2. For the N-S di-
rection a fairly constant value of 180 Qm is obtained between
10 km and 65 km, whereas resistivities of 350 Í2m are seen
below 70 km. The minimum in the apparent resistivity curve
at 100 secs corresponds to a depth of 35 km, but a significant
minimum is not seen in the Bostick curve. The resistivity curve
for the E-W direction shows a general increase with depth
from 10 Qm at 3.5 km to about 350 Qm at 100 km.
Station FAEO 1 (2—500 secs and 40—3600 secs) — Flavn-
ardalur.
The data analysis from this station showed a 2-dimensional
earth structure, with the 2 possible directions of constant
resistivity approximately in the magnetic N-S and E-W direc-
tions. The apparent resistivities are shown in fig. 3a,b and fig.
4a,b, and we note an increased separation between the 2 curves
with increased period.
The Bostick resistivities are presented in fig. 5a and fig. 5b.
For the long-period band, a fairly constant value for pB2 be-
tween 17 km and 28 km is seen, followed by an increase in
resistivity. The constant level at 30 Í2m seems to be in agree-
ment with the short periodic band, where a nearly constant
value of 25 -Om is obtained between 11 km and 19 km. The
most prominent feature of the curves is the large difference in
the resistivities for the two directions. At depths bigger than
10 km resistivities smaller than 100 Í2m are not obtained in
the E-W direction. For this direction we note a general increase
in resistivity with depth, as is also seen at station FAE03, and
the resistivities are seen to be in good agreement.
Discussion of the results
For the magnetotelluric station at Havnardal we found a
twodimensional structure, with the two possible strike direct-