Fróðskaparrit - 01.01.1977, Side 62

70 Complementary gravity observations in the Faroe Islands
Suáuroy 1 WM 779 1972
SDU
1350 ■
1340
1330 —
21/7
22/7 23/7 24/7
Fig. 4. Drift curve for Worden Master gravimeter No. 779 at station
Suðuroy 1.
was placed on the concrete floor in a garage. Another series of
observations took place October 8th to lOth, 1972. In Fig. 5
is depicted the decay curve, and it can be seen that 5 to 6
hours after the battery has been removed the temperature is
constant, however, being dependent on the external (room)
temperature. Fig. 6 depicts in the upper part the cooling effect
during 4 hours, and in the lower part the heating effect, which
is 4 times faster.
In order to obtain an idea of the drift curve in periods where
the battery has been fixed and removed, the drift curves for
the time July 29th to August 6th and for October 4th to 11 th
are shown in Fig. 7, in the upper part and the lower part, re-
spectively. It can be concluded that the overall drift is inde-
pendent of interruptions in the current supply. It is also clearly
demonstrated that it takes between 1 and 2 days before the
drift is normal when the meter has been without power supply
for several days. Furthermore, the average value at decreasing
temperature is a decrease of 0.3 SDU per °F.
The results obtained with regard to the drop in temperature
have been utilized (Figs. 3 and 4), the largest correction being
0.45 mGal.
Some 130 new gravimetric stations were measured; 26 in
Vágar, 63 in Streymoy, and 41 in SuSuroy. The gravimetric
observations have been reduced in the usual manner. The
geographical coordinates have been computed from the topo-
graphic maps on the scale of 1:20.000. The elevations of the