[S-SS08] Crustal Structure

[SSS08-P09] High-Resolution Imaging of the Crustal Structure and Discontinuities Beneath the Carpathian-Pannonian Region

Hari Ram Thapa¹, *Gordana Vlahovic¹ (1.North Carolina Central University)

Keywords:Carpatho-Pannonian region, teleseismic P wave coda, autocorrelation, Moho map, crustal Vp/Vs, ambient noise tomography

Central Europe's Carpathian-Pannonian region (CPR) has significant seismic activity, highlighting the need for detailed crustal studies. Despite extensive international research, the region's crustal structure remains poorly understood due to past limitations in seismic station coverage. Now, dense coverage of seismic stations is available in this region; hence, the knowledge of the crustal structure beneath this region has been improved. However, highly resolved crustal 3-D S-wave velocity structure and discontinuities are still poorly known. Mapping crustal discontinuities and S-wave velocity is crucial for understanding continental deformation dynamics and better constraining earthquake potential. To address this, we present a new high-resolution 3-D S-wave velocity model of the crust and a detailed map of crustal discontinuities using ambient noise tomography and teleseismic P-wave coda autocorrelation. In this study, we used 235 broadband stations from seven different networks. The distribution of these stations provides unprecedented dense ray coverage, enabling us to achieve the best lateral resolution in our study area so far. We obtained the high-resolution Moho map from P wave coda autocorrelation and further worked on the sedimentary thickness map and the intra-crustal discontinuities map by using the same method. The obtained Moho map indicates a shallow Moho beneath the Pannonian, Vienna, and Danube basins, with depths between 20 and 30 km, while the deepest Moho is observed beneath the Southern Carpathians, Apuseni Mountains, and Southeast Carpathians, where it reaches depths of 45 to 55 km. The shallower Moho beneath the basins indicates crustal thinning, while thicker Moho in neighboring mountain belts indicates orogenic thickening. The ambient noise tomography further refines the velocity structure beneath each station, enabling even more precise Moho depth and intra-crustal discontinuities determinations, which are ongoing.