Crustal structure characteristic in North and Central Europe inferred by P-wave polarization analysis

P wave polarization analysis is applied together with array methods to investigate the crustal and upper mantle structure in Germany and south Norway. P-wave polarization may yield valuable information on lateral heterogeneity and anisotropy close to the recording station. 20 years of recordings is used to study the dependence of the polarization attributes as a function of backazimuth and epicentral distance and frequency. The automation of the analysis procedure is needed to process large amount of data and determine incidence angle, azimuthal deviation and linearity in different frequency ranges. Incidence angles as well as azimuthal deviations of P-waves vary with frequency are observed. The azimuthal deviations are mainly a function of the backazimuth. Fast propagation directions of P-waves may be determined by harmonic analysis of the azimuthal deviations as a function of backazimuth. Applying harmonic analysis to the azimuthal deviations measured at the stations of the German Regional Seismic Network and NORSAR array at different frequency bands, we extract their dependence on the events backazimuth. It is possible to retrieve the amplitude of the 180 periodicity term representing the anisotropy of the local structure, assuming an horizontal hexagonal symmetry axis for the anisotropy. The effect of lateral heterogeneities close to the receiver and along the ray path is studied as well. The azimuthal anomalies of polarization vector and incidence angle by polarization analysis are compared with propagation direction and slowness estimated by fk analysis. This helps to understand the characteristic of anisotropy and locate the lateral heterogeinites generating the deviations from GCP direction of polarization and propagation vectors.