Referent seismic crustal model of the Dinarides

Abstract. Continental collision zones are structurally one of the most heterogeneous areas intermixing various units within relatively small space. The good example of this are the Dinarides where thick carbonate complex cover overlain older crystalline basement units and remnants of subducted oceanic crust. This is further complicated by the highly variable crustal thickness ranging from 20 to almost 50 km. In terms of spatial extension, this area is relatively small, but covers tectonically very differentiated domains making the analysis complex, with significant challenges in areas with less data coverage.

Presently there is no complete 3-D crustal model of the Dinarides (and the surrounding areas). Using the compilations of previous studies, we have created vertically, and laterally varying crustal models defined on a regular grid for the wider area of the Dinarides, also covering parts of Adriatic Sea and SW part of the Pannonian Basin. In addition to the seismic velocities (P- and S-) and density, three interfaces in our model were defined – Neogene deposits bottom, Carbonate complex bottom and Moho discontinuity. Neogene deposits and the Paleozoic to Eocene Carbonate complex rocks are not present in all areas of the model whereas Moho discontinuity depth is defined for the entire model. The newly derived model has been compared with the simple 1D model used for routine earthquake location in Croatia, and it proved to be a significant improvement.

The model derived in this work represents the first step towards improving our knowledge of the crustal structure in the complex area of the Dinarides. We hope that the newly assembled model will be useful for all the forthcoming studies which require knowledge of the crustal structure.