| Abstract: | For the first time, fundamental and higher-mode Rayleigh wave phase velocity data for the West European Platform have been measured, using teleseismic recordings from the mobile broad-band NARS array. Measurements could be obtained from 30 to 70 mHz. This is an extension of 30 mHz towards higher frequencies with regard to previous measurements, in the frequency range of 10 to 40 mHz for western Europe, including the Scandinavian Shield (Nolet, 1977). Inversion of the new data for isotropic shear-wave velocity and density (model WEPL1) shows a broad, low shear-wave velocity layer from 120 to 260 km depth, without a Lehmann discontinuity. At larger depths, the model resembles the M7 model (Nolet, 1977). The density model shows a steep positive gradient from 60 to 100 km depth, followed by a slight decrease down to 300 km depth. No pronounced low-density layer, as present in the M7 model, could be resolved. Reinversion of Nolet's data using the same starting model as for the WEPL1 model and calculation of the difference structure yields a model for the Scandinavian Shield (SCSH1). The Shield has higher shear-wave velocities than the West European Platform down to about 300 km depth. |
