Rit (Vísindafélag Íslendinga) - 01.06.1971, Page 9

1. INTRODUCTION
Crustal studies by seismic refraction techniques have been carried
out in Iceland since 1959. The first profile of this kind was made by
Dr. M. Báth of Uppsala, Sweden, in collaboration with the State Elec-
tricity Authority (now National Energy Authority), Department of
Natural Heat, under the leadership of Dr. Gunnar Bödvarsson (Báth,
1960). In the following year eight short profiles were measured to
study the structure of the upper part of the crust to a depth of a few
kilometers. This was done in collaboration with the Icelandic Me-
teorological Service (Tryggvason and BAth, 1961). The results of
this initial work were so promising that in 1961 the State Electricity
Authority purchased a set of long-distance seismic refraction equip-
ment of the same kind as was used by Báth. Since then seismic re-
fraction data have been collected more or less every summer for 7
years. In the beginning the emphasis was on relatively short profiles
for a detailed study of the upper part of the crust. Later, larger pro-
file lengths were used, especially in some offshore studies in 1966
and 1967 off the west and south coasts. Detailed work was also carried
out in some areas where an anomalous structure had been found, e.g.
in the Snaefellsnes volcanic zone.
Crustal studies in Iceland are of importance for several reasons.
Iceland is one of the few areas where a mid-ocean ridge can be
studied on land. A number of refraction crustal studies have been
made on these ridges where they are lying beneath several kilo-
meters of water. The interpretation of these measurements is always
uncertain and correlation with other sets of data difficult. Detailed
studies on land under presumably similar geological conditions would
therefore provide a useful background for studying the oceanic crust.
Apart from its importance in connection with mid-ocean ridge
studies, the seismic refraction work can contribute significantly to
the solution of local geological problems in Iceland. In the prospect-
ing of geothermal areas the seismic profiles can be used to outline
boundaries between seismic layers and their depth variation. The