Titel
Azimuthal anisotropy in the wider Vienna basin region: a proxy for the present-day stress field and deformation
Autor*in
Dimitri Zigone
Institut de Physique du Globe de Strasbourg, Université de Strasbourg, EOST, CNRS
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Abstract
We infer seismic azimuthal anisotropy from ambient-noise-derived Rayleigh waves in the wider Vienna Basin region. Cross-correlations of the ambient seismic field are computed for 1953 station pairs and periods from 5 to 25 s to measure the directional dependence of interstation Rayleigh-wave group velocities. We perform the analysis for each period on the whole data set, as well as in overlapping 2°-cells to regionalize the measurements, to study expected effects from isotropic structure, and isotropic–anisotropic trade-offs. To extract azimuthal anisotropy that relates to the anisotropic structure of the Earth, we analyse the group velocity residuals after isotropic inversion. The periods discussed in this study (5–20 s) are sensitive to crustal structure, and they allow us to gain insight into two distinct mechanisms that result in fast orientations. At shallow crustal depths, fast orientations in the Eastern Alps are S/N to SSW/NNE, roughly normal to the Alps. This effect is most likely due to the formation of cracks aligned with the present-day stress-field. At greater depths, fast orientations rotate towards NE, almost parallel to the major fault systems that accommodated the lateral extrusion of blocks in the Miocene. This is coherent with the alignment of crystal grains during crustal deformation occurring along the fault systems and the lateral extrusion of the central part of the Eastern Alps.
Stichwort
EuropeSeismic anisotropySeismic interferometrySeismic noiseSurface waves and free oscillations
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Geophysical Journal International
Band
220
Ausgabe
3
Seitenanfang
2056
Seitenende
2067
Publication
Oxford University Press (OUP)
Erscheinungsdatum
2019
Zugänglichkeit
Rechte
Rechteangabe
© The Author(s) 2019
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