Jökull - 01.12.1963, Blaðsíða 51

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APPENDIX
The Appendix contains the following:
1. Remarks on individual profiles.
2. Table 4. Summary of travel time lines.
3. Travel time sraphs of profiles 1—30.
REMARKS ON INDIVIDUAL PROFILES
1. This profile is located on Skardsströnd on
the coast of Breidifjördur in the Tertiary basalt
area in western Iceland. The Pi and Si velo-
cities are here somewhat higher than the rnean
values for the upper part of the Tertiary basalts.
2. This profile runs along the valley Vatns-
dalur in the Tertiary basalts of northern Ice-
land. The shot point was in the sea at the
northern end of the profile. As mentioned
earlier an anomaly was observed on this pro-
file, in that the P3 phase at distances 18.21 km
JÖKULL 1963
and 21.99 km arrived 0.07 and 0.15 sec too
early respectively compared with neighbour-
ing points. When this was later investigated
further by means of a short profile, about
5 km long, in the area of the anomalous
points, it was found that the structure there
consisted of an upper layer of velocity 3.7 km/
sec, and a lower layer with velocity 6.2 km/sec
at a depth of about 0.6 km. If this lower layer
is layer 3, this is the shallowest depth at which
it has been found so far in Iceland.
Close to these two anomalous points on this
profile there is a large basaltip intrusion out-
47