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Anisotropic tomography of the European upper mantle
Žlebčíková, Helena ; Plomerová, Jaroslava (advisor)
Title: Anisotropic tomography of the European upper mantle Author: Helena Žlebčíková Department: Department of Geophysics, Faculty of Mathematics and Physics, Charles University Training institution: Institute of Geophysics of the Czech Academy of Sciences (IG CAS) Supervisor: RNDr. Jaroslava Plomerová, DrSc., IG CAS Consultants: RNDr. Vladislav Babuška, DrSc., IG CAS RNDr. Luděk Vecsey, Ph.D., IG CAS Abstract: Large-scale seismic anisotropy of the continental mantle lithosphere derived from joint inversion/interpretation of directional variations of P-wave travel-time residuals and SKS-wave splitting calls for orientation of the symmetry axes to be treated generally in 3D. Nevertheless, most of the tomography studies neglect the anisotropy of the body waves completely or they are limited to either azimuthal or radial anisotropy. Therefore, we have developed a code called AniTomo for coupled anisotropic-isotropic travel-time tomography of the upper mantle. The novel code allows inversion of relative travel-time residuals of teleseismic P waves simultaneously for 3D distribution of P-wave isotropic- velocity perturbations and anisotropy of the upper mantle. We assume weak anisotropy of hexagonal symmetry with either the 'high-velocity' a axis or the 'low-velocity' b axis. The symmetry axis is allowed to be...
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Anisotropic tomography of the European upper mantle
Žlebčíková, Helena ; Plomerová, Jaroslava (advisor)
Title: Anisotropic tomography of the European upper mantle Author: Helena Žlebčíková Department: Department of Geophysics, Faculty of Mathematics and Physics, Charles University Training institution: Institute of Geophysics of the Czech Academy of Sciences (IG CAS) Supervisor: RNDr. Jaroslava Plomerová, DrSc., IG CAS Consultants: RNDr. Vladislav Babuška, DrSc., IG CAS RNDr. Luděk Vecsey, Ph.D., IG CAS Abstract: Large-scale seismic anisotropy of the continental mantle lithosphere derived from joint inversion/interpretation of directional variations of P-wave travel-time residuals and SKS-wave splitting calls for orientation of the symmetry axes to be treated generally in 3D. Nevertheless, most of the tomography studies neglect the anisotropy of the body waves completely or they are limited to either azimuthal or radial anisotropy. Therefore, we have developed a code called AniTomo for coupled anisotropic-isotropic travel-time tomography of the upper mantle. The novel code allows inversion of relative travel-time residuals of teleseismic P waves simultaneously for 3D distribution of P-wave isotropic- velocity perturbations and anisotropy of the upper mantle. We assume weak anisotropy of hexagonal symmetry with either the 'high-velocity' a axis or the 'low-velocity' b axis. The symmetry axis is allowed to be...
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Anisotropic tomography of the European upper mantle
Žlebčíková, Helena ; Plomerová, Jaroslava (advisor) ; Agostinetti Piana, Nicola (referee) ; Achauer, Ulrich (referee)
Title: Anisotropic tomography of the European upper mantle Author: Helena Žlebčíková Department: Department of Geophysics, Faculty of Mathematics and Physics, Charles University Training institution: Institute of Geophysics of the Czech Academy of Sciences (IG CAS) Supervisor: RNDr. Jaroslava Plomerová, DrSc., IG CAS Consultants: RNDr. Vladislav Babuška, DrSc., IG CAS RNDr. Luděk Vecsey, Ph.D., IG CAS Abstract: Large-scale seismic anisotropy of the continental mantle lithosphere derived from joint inversion/interpretation of directional variations of P-wave travel-time residuals and SKS-wave splitting calls for orientation of the symmetry axes to be treated generally in 3D. Nevertheless, most of the tomography studies neglect the anisotropy of the body waves completely or they are limited to either azimuthal or radial anisotropy. Therefore, we have developed a code called AniTomo for coupled anisotropic-isotropic travel-time tomography of the upper mantle. The novel code allows inversion of relative travel-time residuals of teleseismic P waves simultaneously for 3D distribution of P-wave isotropic- velocity perturbations and anisotropy of the upper mantle. We assume weak anisotropy of hexagonal symmetry with either the 'high-velocity' a axis or the 'low-velocity' b axis. The symmetry axis is allowed to be...
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Teleseismic Tomography of the Upper Mantle beneath the Bohemian Massif
Karousová, Hana ; Plomerová, Jaroslava (advisor) ; Růžek, Bohuslav (referee) ; Zahradník, Jiří (referee)
Passive seismic experiments, MOSAIC, BOHEMA I-III, EgerRift, or, PASSEQ, carried out in the region of the Bohemian Massif (BM), allowed a detailed study of velocity structure of the upper mantle. We present results of tomography studies of the upper mantle beneath the north-eastern and southern parts of the BM based on the data from the BOHEMA II and BOHEMA III experiments (2004-2006). Despite the fact that regions with the highest resolution of velocity perturbations differ in the models, tomography images are similar in overlapping parts. Models of the upper mantle show mostly low- velocity perturbations relatively to radially symmetric velocity model of the Earth beneath the BM. Limited high-velocity heterogeneity beneath the Moldanubian unit, extended in the NE-SW direction, reflects thickening of the lithosphere due to a collision of the BM with the Brunovistulian micro-plate during the Variscan orogeny. The tomography based on the data from the BOHEMA III experiment revealed significant high-velocity heterogeneity in the southern margin of the model with a subduction of the lithosphere beneath the Eastern Alps. Tomographic tests showed that effects of uncorrected velocity heterogeneities within the crust can appear as deep as 100 km and, therefore, they could lead to erroneous interpretation of...
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Seismic Tomography - historical development and application
Mityska, Martin ; Vilhelm, Jan (advisor) ; Karousová, Hana (referee)
The goal of this bachelor thesis is to offer an overview on technics of seismic tomography, their history and general usage. It's focused mainly on description of pioneering efforts in building mathematical tools of tomography and their application in geophysics. Methods mainly discussed are: Herglotz - Wiechert inversion, first numerical studies like ACH teleseismic method, Aki & Lee method of local sources inversion and early global mantle velocity studies. There are also discused some shortcomings of tomagraphy models and their influences on interpretation of results.
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SLICE Seismic lithospheric investigation of Central Europe
Akademie věd ČR, Geofyzikální ústav, Praha ; Uličný, David ; Růžek, Bohuslav ; Hubatka, František ; Špaček, Petr ; Švancara, Jan ; Brož, Milan ; Novotný, Miloslav ; Karousová, Olina ; Hrubcová, Pavla ; Špičák, Aleš ; Novotný, Miroslav
Projekt SLICE má za úkol zkoumat hlubinnou stavbu středoevropské oblasti a jeho cílem je přispět k výzkumu stavby zemské kůry a svrchního pláště v oblasti Českého masivu a jeho styku se sousedními tektonickými jednotkami. Pro studium hlubinné stavby je využívána seismická refrakční metoda, kdy se registrují seismické vlny generované uměle vyvolanými odpaly a posléze je zjišťována rychlost šíření seismických vln v různých hloubkách. Tyto údaje pak zprostředkovaně poskytnou informace o strukturních vlastnostech měřeného prostředí až do oblasti svrchního pláště. Je popsáno propojení refrakčních experimentů ALP 2002 a SUDETES 2003 na našem území.
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