Moho depth analysis of the eastern Pannonian Basin and the Southern Carpathians from receiver functions

Dániel Kalmár,György Hetényi,István Bondár

doi:10.1007/s10950-019-09847-w

Abstract

Receiver function analysis is performed for the easternmost part of the Pannonian Basin and across the Southern Carpathians, a geologically and geodynamically complex region featuring microplates, mountain belts, and locally deep sedimentary basins. We exploited seismological data of 56 stations including temporary broadband stations of the South Carpathian Project (SCP) and two permanent stations in Hungary. We calculated P-to-S receiver functions to determine the variation of Moho depth across the basin and the mountains along a NW–SE-oriented swath about 600 km long and 200 km wide. We applied threefold quality control on the raw and the processed data. The Moho depth was determined by two independent approaches, common conversion point migration and H-K grid search method. The determined Moho depths show shallow values between the AlCaPa and the Tisza-Dacia blocks, with typical depths between 22 and 28 km, and the shallowest depths in the area of eastern Pannonian Basin. We could estimate the Moho depth beneath one station in the Mid-Hungarian Zone, between the AlCaPa and the Tisza-Dacia blocks. The crust was thicker under the Apuseni Mountains (28–32 km), and in the investigated region, the Moho was deepest beneath the Southern Carpathians (33–43 km). We observed a southeastward crustal thickness increase, and we presented an interpolated Moho map over the area of study.

Highlights

Our study area is the transition zone between the Carpathian Mountains and the Pannonian Basin in Central Europe (Fig. 1)
It shows receiver functions sorted by back-azimuth and stacks at the 4F07 hard rock station and the 6D04 sediment station before and after QC2-3
We show the receiver function stacks before and after QC2-3 for all stations in the electronic supplement

Summary

Introduction

Our study area is the transition zone between the Carpathian Mountains and the Pannonian Basin in Central Europe (Fig. 1). In the early Miocene, lithospheric extension resulted in basin thinning because the extension velocity was larger than the sediment fill rate (Csontos et al 1992) During this time, north-eastward movement of the Adria block and collision with Europe occurred. The two blocks underwent SW–NEoriented extension, but were still separated by the MidHungarian Zone (MHZ), located between these two blocks and being the continuation of the Periadriatic Line (Csontos and Nagymarosy 1998; Tari et al 1999). As for the neotectonic phase of the basin, GPS measurements indicate that with respect to the Eurasian Plate, the Adriatic microplate moves 4 mm/year in northeast direction (Bada et al 2007) This movement has an impact on the AlCaPa structural elements. The eastern part of the block moves 0.3 mm/year, and the western part of the block moves 1.3 mm/year, while other parts of the block are relatively stable

Results

Discussion

Conclusion