Average crustal structure of Sweden

Summary

Records obtained at the permanent stations of the Swedish seismograph network from explosions carried out in Scandinavian waters in June 1969 are evaluated. The study includes determination of velocities for all crustal phases observed, furthermore of layer thicknesses, Poisson ratios and amplitude ratios. The purpose of the study is partly to provide a first approximation to the crustal structure in Sweden, partly to provide regional data for location of earthquakes and explosions in the area in the future. Average velocities (km/sec) are forPn 7.88±0.05,Pg1 6.25±0.08,Pg2 5.70,Sn 4.58±0.04,S ^* 3.70±0.04,Sg1 (Lg1) 3.58±0.03,Sg2 (Sg) 3.40±0.03,Rg 3.02±0.07. The average thickness is 12 km for the granitic layer, and 23 km for the basaltic layer, thus making the average crustal thickness equal to 35 km. Relative amplitudes plotted versus distance complete the dynamical side of the study and they are useful for identification of waves. A regional travel-time table is presented for the distance range 0°–10° with entries for each 0.1° and including all crustal phases read.