P-receiver functions of anisotropic continental crust: A hierarchic catalogue of crustal models and azimuthal waveform patterns

Abstract

Azimuthal P-receiver functions are influenced by crustal anisotropy and heterogeneity. To study these effects we created a catalogue of 30 crustal models and corresponding azimuthal P-receiver functions. The crustal models are grouped in five classes of anisotropic and isotropic horizontal and dipping plane layers. The model design was motivated by geological structure found by deep seismic reflection profiling and deep drilling. In the synthetic seismogram catalogue, we identified 14 azimuthal waveform features that could be used to narrow the range of possible crustal model for seismic inversion or interactive forward modelling. Based on a hierarchical classification of these waveform features 80 per cent of the input models could be uniquely identified. In case of field data the hierarchical classification can be used to find a starting model for forward modelling or non-linear inversion. To test the applicability of the method we applied it to records of four permanent stations of the German Regional Seismic Network. In two cases the procedure led to a satisfactory agreement of observed and modelled azimuthal data in both R and T components. The obtained subsurface models are plausible because they correspond to anisotropy values and structures found for similar settings by deep drilling and deep seismic profiling. In the other two cases only partial agreement of real and synthetic data could be obtained. These stations are located in a complicated tectonic setting that cannot be modelled satisfactorily by an approach based on plane dipping layers. © 2011 The Authors Geophysical Journal International © 2011 RAS.