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Transversely isotropic lower crust of Variscan central Europe imaged by ambient noise tomography of the Bohemian Massif
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SYSNO ASEP 0544673 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Transversely isotropic lower crust of Variscan central Europe imaged by ambient noise tomography of the Bohemian Massif Author(s) Kvapil, Jiří (GFU-E) ORCID
Plomerová, Jaroslava (GFU-E) ORCID, RID, SAI
Kampfová Exnerová, Hana (GFU-E) ORCID, RID
Babuška, Vladislav (GFU-E) ORCID, RID, SAI
Hetényi, G. (CH)Source Title Solid Earth. - : Copernicus - ISSN 1869-9510
Roč. 12, č. 5 (2021), s. 1051-1074Number of pages 24 s. Publication form Print - P Language eng - English Country DE - Germany Keywords surface wave tomography ; upper mantle ; Bohemian Massif Subject RIV DC - Siesmology, Volcanology, Earth Structure OECD category Volcanology R&D Projects GA21-25710S GA ČR - Czech Science Foundation (CSF) LM2010008 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) LM2015079 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) EF16_013/0001800 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Method of publishing Open access Institutional support GFU-E - RVO:67985530 UT WOS 000651081700001 EID SCOPUS 85105773688 DOI 10.5194/se-12-1051-2021 Annotation The recent development of ambient noise tomog-raphy, in combination with the increasing number of permanent seismic stations and dense networks of temporary stations operated during passive seismic experiments, provides a unique opportunity to build the first high-resolution 3-D shear wave velocity (upsilon(S)) model of the entire crust of the Bohemian Massif (BM). This paper provides a regional-scale model of velocity distribution in the BM crust. The velocity model with a cell size of 22 km is built using a conventional two-step inversion approach from Rayleigh wave group velocity dispersion curves measured at more than 400 stations. The shear velocities within the upper crust of the BM are similar to 0.2 km s(-1) higher than those in its surroundings. The highest crustal velocities appear in its southern part, the Moldanubian unit. The Cadomian part of the region has a thinner crust, whereas the crust assembled, or tectonically transformed in the Variscan period, is thicker. The sharp Moho discontinuity preserves traces of its dynamic development expressed in remnants of Variscan subductions im- printed in bands of crustal thickening. A significant feature of the presented model is the velocity-drop interface (VDI) modelled in the lower part of the crust. We explain this feature by the anisotropic fabric of the lower crust, which is characterised as vertical transverse isotropy with the low velocity being the symmetry axis. The VDI is often interrupted around the boundaries of the crustal units, usually above locally increased velocities in the lowermost crust. Due to the north-west-south-east shortening of the crust and the late-Variscan strike-slip movements along the north-east-south-west oriented sutures preserved in the BM lithosphere, the anisotropic fabric of the lower crust was partly or fully erased along the boundaries of original microplates. Workplace Geophysical Institute Contact Hana Krejzlíková, kniha@ig.cas.cz, Tel.: 267 103 028 Year of Publishing 2022 Electronic address https://se.copernicus.org/articles/12/1051/2021/
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