Jökull - 01.12.1973, Page 74

TABLE 1 - TAFLA 1
Fig. 2. Location of gravity base stations in the
Reykjavík area.
Mynd 2. Staðsetning þyngdarmœlistöðva i
grunnneti i Reykjavik.
of instrument) = 0. In some cases a levelling
disk was required, as described in Appendix II.
In most cases the gravity base stations were
measured using a loop technique, with the dura-
tion of each loop less than 13 hours. Nineteen
loops originated at station Reykjavík L, which
is located at the airport (Fig. 2). Four loops
originated at the Akureyri (AP) station. Five
additional loops connect the Reykjavík stations,
including Keflavík K (= Rey(K)), which is
located at Keflavík airport 40 km southwest of
Reykjavík. One loop and two lines were mea-
sured in the 1970 survey.
The stations within loops were observed in
ladder sequence (ABCDCBA). Transportation
between stations was by airplane, lielicopter,
or automobile. For convenience in surveying,
many of the base stations are located close to
airports. The chronological order of establish-
72 JÖKULL 23. ÁR
Milligal values for LaCoste and Romberg, Inc.,
Model G gravity meters 137, 140, and 144
Milligal gildi fyrir LaCoste og Romberg., Inc.,
Model G. þyngdarmœla 137, 140 og 144
Instru- Counter Value Factor for
ment reading in interval
no. (dial div.) milligals (milligals)
137 5300 5574.37 1.05185
5400 5679.56 1.05175
5500 5784.73 1.05160
5600 5889.89 1.05145
5700 5995.04 1.05130
5800 6100.17 1.05110
5900 6205.28 1.05090
6000 6310.37 1.05070
140 5300 5561.89 1.05205
5400 5667.09 1.05200
5500 5772.29 1.05190
5600 5877.48 1.05185
5700 5982.67 1.05175
5800 6087.84 1.05160
5900 6193.00 1.05145
6000 6298.14 1.05125
144 5300 5543.37 1.04745
5400 5648.12 1.04735
5500 5752.86 1.04715
5600 5857.57 1.04700
5700 5962.27 1.04690
5800 6066.97 1.04680
5900 6171.65 1.04670
6000 6276.32 1.04650
ment of stations and the sequence of loops is
summarized in Table 3.
Three secondary base stations were establish-
ed at Grímsfjall, Hólmavík and Laugafell dur-
ing the regional gravity survey of Iceland. They
are described in Appendix II, but have not
been included in the adjustment calculations
(cf. below).