Preliminary Moho depth determination from receiver function analysis using AlpArray stations in Hungary

Abstract

Receiver function analysis is applied to the western part of the Pannonian Basin, a rather complex region both geologically and geodynamically. Previous receiver function analyses in this region had to deal with much smaller station density and time span than those available to us. In the analysis we used the data of some 48 seismological stations. These include not only the permanent stations from Hungary and permanent stations from neighbouring countries (Slovakia and Slovenia), but also the temporary broadband stations that were installed within the framework of the AlpArray project. Having applied rather strict manual quality control on the calculated radial receiver functions we stacked the receiver functions. Using the H-K grid search method we determined the Moho depth and the Vp/Vs ratio beneath the seismological stations in the western part of the Pannonian Basin. The unprecedented density of the AlpArray network, combined with the permanent stations, allowed us to derive high resolution Moho and Vp/Vs maps for the West Pannonian Basin, together with uncertainty estimates. Our preliminary results agree well with previous studies and complement them with finer details on the Moho topography and crustal thickness.

3D P-wave velocity image beneath the Pannonian Basin using traveltime tomography

“…The average thickness of the lithosphere has been estimated to approximately 60-70 km in the center of the basin (Tari et al 1999;Lenkey 1999). There are also indications for thin lithosphere and shallow asthenosphere from active seismic (Behm et al 2007;Grad et al 2006), receiver function (Kalmár et al 2018;Hetényi et al 2015) magnetotelluric (Praus et al 1990;Ádám et al 2017;Ádám and Wesztergom 2001) and tomographic (Szanyi et al 2013;Dando et al 2011;Ren et al 2013) studies.…”

“…The crust in the Pannonian Basin is quite thin. Its thickness ranges from 24 to 30 km beneath the basin and from 30 to 50 km beneath the surrounding orogenic regions (Grad et al 2009;Kalmár et al 2018). The lithosphere is also thinned but the topography of the lithosphere-asthenosphere boundary is not very well constrained.…”

Crustal Thinning From Orogen to Back‐Arc Basin: The Structure of the Pannonian Basin Region Revealed by P‐to‐S Converted Seismic Waves

“…The next seismological breakthrough was brought about by a number of recently installed permanent stations and the AlpArray project starting at the end of 2015 (Gráczer et al., 2018; Hetényi, Molinari, et al., 2018). As a result, a number of new studies have recently been published at higher resolution, also on smaller areas of the region, such as the Moho depth determination from receiver function analysis in western part of the Hungary (Kalmár et al., 2018), S ‐wave velocity model based on ambient‐noise tomography in the Vienna Basin region (Schippkus et al., 2018) and between the Eastern Alps and the Pannonian Basin (Szanyi et al., 2021), P ‐wave velocity imaging from traveltime tomography in the Pannonian Basin (Timkó et al., 2019) and crustal thickness determination based on receiver functions under the Dinarides and neighboring areas (Stipčević et al., 2020).…”