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| Titel |
Indications for complex anisotropy beneath Scandinavia derived from shear wave splitting analysis |
| VerfasserIn |
Michael Grund, Joachim R. R. Ritter |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141400
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| Publikation (Nr.) |
 EGU/EGU2017-4907.pdf |
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| Zusammenfassung |
| Within the framework of the seismological ScanArray project (~150 temporary and
permanent stations) we perform a shear wave splitting (SWS) analysis to study the signatures
of anisotropic structures across the different geological units of Scandinavia. For this purpose
we use core-refracted shear waves (SKS, SKKS, PKS) from teleseismic earthquakes and
combine standard SWS techniques with stacking procedures to improve the backazimuthal
(BAZ) coverage. Compared to previous studies in Scandinavia, for several regions we obtain
an enhanced spatial resolution of the anisotropic pattern due to the dense recording network
and the stacking procedures.
Although, in general the pattern of the splitting parameters, fast polarisation direction (φ)
and delay time (δt), coincide with those of previous studies, at several recording stations there
are strong variations in the determined SWS parameters with BAZ as well as discrepancies
between SKS and SKKS measurements for the same event. This observation indicates that
the source of anisotropy is quite complex with possibly contributions from both, lithospheric
and deeper mantle structures. Layer models with one or two anisotropic layers are not able
to explain all of our observed SWS parameters with high reliability. This finding
points towards lateral variations which are related to different geological units. |
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