100 Years of Studies of the Crust and Upper Mantle in Croatia

The study of properties of the earth’s crust and upper mantle started in Croatia one century ago, by the seminal paper in which A. Mohorovicic proved the existence of the crust-mantle boundary. Most of Mohorovicic’s work which followed was dedicated to improving travel-time curves of crustal phases. During the 1980-es most of the research—mostly based on interpretation of several deep seismic profiles running across the country—was directed towards determination of the Moho-topography. The interest for the study of elastic properties of the crust was revived in the 1990-es, when several papers appeared which dealt with determination of velocities and attenuation (coda-Q) in the greater circum-Adriatic region. More recently, a large database of Pg-phase arrival times was used to assess the azimuthal anisotropy of the P-wave velocity within the crust in the NW Croatia and in parts of the External Dinarides. It was found that the direction of the fast velocities closely correspond to the direction of predominant current tectonic stress field. Current research based on the data obtained within a large international seismic experiment (ALP2002) lead to new constraints on the crustal structure in northern and western Croatia. Lithospheric structure beneath coastal and continental Croatia is being studied also by broadband teleseismic waveform modeling using receiver functions. The results indicate that the Mohorovicic discontinuity in Dalmatia may lie considerably deeper than presented on recent maps of the Moho topography in Europe.