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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 2:34 |
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Conference: Bucharest University Faculty of Physics 2023 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Investigating Rayleigh Wave Dispersions across the Carpathian Orogen
Authors:
Andrei MIHAI(1,2), Laura PETRESCU(1), Mircea RADULIAN(1)
*
Affiliation:
1)National Institute for Earth Physics, RO- 077125, Calugareni st, no 12, Magurele, Ilfov, Romania
2)Faculty of Physics, University of Bucharest, Atomistilor 405, POB MG-11, RO-077125, Bucharest-Magurele, Romania
E-mail
mihai.a.andrei@gmail.com
Keywords:
tomography, dispersion, group velocities, Rayleigh Wave
Abstract:
The Carpathians were formed by the collision between the Eurasian and the Tisza-Dacia units, pushed by the converging African continent. Several extensions of the Tethys Ocean were closed, so that the Dacia unit was folded and pushed over the edge of the East European Craton and the Moesian Platform, which are tectonic units of different ages and structures that behaved differently when they collided with the Dacia tectonic subunit. This can be observed in the Neogene-Quaternary magmatism associated with the subduction process, both in terms of age and chemical composition. Therefore, surface wave seismic tomography is a useful tool to decipher the complex tectonic evolution of the Carpathian orogen.
To better understand how lithospheric structure on Romanian territory changes from the East European Craton to younger European microplates, we used earthquake data recorded at permanent broadband seismic stations of the Romanian National Seismic Network (RSN). We used the Multiple Filtering Technique (MFT) to investigate the dispersion of Rayleigh and Love wave group velocities for earthquakes that occurred within 4000 km of the epicenter and had a magnitude of mb > 4, recorded at the RSN(Romanian Seismic Network) between 2010 and 2017.
For travel time tomography, we employed Fast Marching Surface Tomography (FMST) using an iterative non-linear inversion technique in spherical coordinates. Over 4000 seismic paths were included in the analysis, resulting in group velocity maps ranging from 30 to 80 seconds, which effectively captured depth variations between 40 and 200 km. The velocity maps obtained revealed the presence of a low-velocity body situated ahead of the Vrancea plate, indicating the upwelling of asthenospheric material due to plate subduction.
Acknowledgement:
This paper was carried out within EENSANE program (PN-III-P4-ID-PCE-2020-2972) and Nucleu Program SOL4RISC (PN2336020).
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