Rit (Vísindafélag Íslendinga) - 01.06.1971, Qupperneq 54

54
GUÐMUNDUR PÁLMASON
ment due to local conditions. The relation (6.5.1) can still be used
if X is put equal to S^D — S2D. The time difference 8TSls2 is always
evaluated at a distance from Sx and S2 which is equal to half the
distance SiS2.
This method has been used to compute the average velocity in
layer 3 on different segments between shot points along the line from
Ólafsvík to Kolbeinsstadir. In each case separate calculations were
made for three different stations D, and an average value taken. On
the segment between Hofsstadir (S3) and Kolbeinsstadir (S4) the
value of 8T was obtained indirectly from the segments Hraunsmúli-
Hofsstadir and Hraunsmúli-Kolbeinsstadir as follows.
8THoh,-
8Tkh,
where TaHo, TaHr and Td[. are the delay times at Hofsstadir, Hrauns-
múli and Kolbeinsstadir. The values of 8TH0Hr and 8TKHr are ob-
tained directly from the travel time diagrams, and the value of 8TKHo
is then found from
8TK
KHO — T(ik -TdH0
8 Tkh, — 8T„
The results obtained for the velocity in layer 3 hy the above met-
hods are shown below in Tables 6.1—6.3.
Table 6.1. Ólafsvík-Hraunsmúli.
D-station No. AT sec ð ^óHr Sec Xkm V3 km/sec
1625(1615) 3.87 0.00 24.69 6.55
1628(1619) 3.93 •n 25.19 6.41
1629(1630) 3.72 •n 24.59 6.61
Average V 3 = 6.52 km/sec
Table 6.2. Hraunsmúli—Kolbeinsstadir.
D-station No. AT sec 8^HoHr sec X km V3 km/sec
1639 2.90 0.22 17.79 6.64
1638 2.86 99 17.87 6.77
1574(1184) 2.95 99 18.54 6.80
Average "V ’3 = 6.74 km/sec