Fróðskaparrit - 01.01.1976, Page 17

Seismic Refraction Measurements around the Faeroe Islands 25
^ A/e UKAEA
i i (sec.)
corr.
• Line A
X Line B
° Line C (north)
6-
<
5-
x
x
X
X
X
X
X
X
X
X X
X
X
3-
150 200 250 300 350 400 A(km)
Fig. 8. Reduced travel times (using 8 kmls) for the array stations UKAEA
(Shetlands, 60° 15103 N, 03° 34!79 W). Only the shots B 1 .. B 29, C 54 A
. . C 59 and A 1 . . A 5 are shown.
Whatever the true velocity below the Faeroe Block might
be it is found that the Moho time terms increase more than
0.5 s from line A ((2. . 3 sec) to line B (3. . 4 sec) and the time
terms of F1 and F2 are found to be significantly smaller than
the time terms of F3, F4 and DU4. According to the observa-
tions made at the array station UKAEA on the Shetlands the
Moho time terms increase about 0.5 s when going from the
shots A1. .A5 and line C (north) to line B (see fig 8).
On the British side of the Faeroe-Shetland channel a time
term analysis of the NASP-data has revealed a rather uniform
structure with Moho time terms of 2.. 3 s where the higher
values are caused by sediments, and the velocity was found
to be 7.99 + 0.02 km/s (Smith & Bott 1975). The Moho
time terms for the Faeroese side of the channel are higher, but
the decrease across the channel may start at the »escarpment«
on the Faeroese side (Casten & Nielsen 1975).
The results of line C (south) are rather uncertain, but the
Moho time terms are probably not very different from those
of line B.