Structure of the Lithosphere Beneath Croatia Determined from Broadband Radial Receiver Functions

Broadband seismograms of teleseismic events recorded at Croatian seismological network were used to compute radial receiver functions for 8 locations, mostly along the Adriatic coast (External Dinarides). Waveform modeling was performed by fitting the theoretical receiver functions computed for horizontally layered 1-D isotropic models of the lithosphere to the stacked observed ones. Inversion was done by the Monte-Carlo search of model parameters (transversal wave velocity (Vs), layer thicknesses and the Vp/Vs ratio). The misfits between the modeled and the observed receiver function waveforms were then used to select all models falling within the 90% confidence interval as representative ones for the respective receiver. In most cases the Moho depth is well defined, with uncertainties of the order of few km. The confidence intervals for Vs are quite large, and Vp/Vs is very poorly constrained. Our preliminary results indicate that Moho depths in the Rijeka and Zagreb areas agree very well with the recent maps of the Moho topography in Europe. However, in Dalmatia we find Moho to be considerably deeper, reaching depths of almost 50 km. For some stations in central Dalmatia the fit of 1-D synthetics to the observed receiver functions is worse then elsewhere, indicating that anisotropy and expressed Moho topography probably play an important role.