Rit (Vísindafélag Íslendinga) - 01.06.1971, Side 41

CRUSTAL STRUCTURE OF ICELAND
41
layer. The main change in thickness of the surface layer appears to
occur near Hafnir.
The P3 delay time increases eastward on the Reykjanes—Krisuvík
profile. At a distance of 19 km the total delay time is 1.25 sec. If the
shot point delay time as found earlier is 0.58 sec, the delay time at
the eastern end of the profile is 0.67 sec (cf. also Grindavík-Vogar
A reversed profile (45a and 45b), ahout 15 km long, runs from
Grindavík on the south coast to Vogar on the north coast. Some
asymmetry is apparent on this profile, probably caused by layers 1
and 2. The surface layer (layer 0) is thicker at the northem end,
0-54 km (Ta = 0.17 sec), than at the southern end, where it is 0.35 km
(Ta = 0.11 sec). It is underlain by layer 1 with a velocity of 4.1 km/
sec. Layer 2 appears to be absent on the southern part of the profile,
but there are some indications from the travel time diagram that it
tnay be present under the northern part of the profile.
Delay times for P3-waves are found to be 0.64 sec at Grindavík
and 0.54 sec at Vogar. With only layer 1 present under the surface
layer at Grindavík this gives a depth of layer 3 of 3.1 km. At the
northem end of the profile the depth to layer 3 cannot be computed