Elastic-anelastic Regional Structures for the Iberian Peninsula Obtained from a Rayleigh Wave Tomography and a Causal Uncoupled Inversion |
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Authors: | Email author" target="_blank">MD?MartínezEmail author X?Lana O?Caselles J?A?Canas L?Pujades |
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Institution: | (1) Dept. Física Aplicada, ETSAB, Universitat Politècnica de Catalunya, Av. Diagonal 649, E-08028 Barcelona, Spain;(2) Dept. Física i Enginyeria Nuclear, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, E-08028 Barcelona, Spain;(3) Dept. Enginyeria del Terreny, Cartogràfica i Geofísica, ETSECCPB, Universitat Politècnica de Catalunya, C/ Gran Capità s/n, E-08034 Barcelona, Spain |
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Abstract: | The elastic and anelastic structure of the lithosphere and asthenosphere of the Iberian Peninsula is derived by means of tomographic
techniques applied to local phase and group velocities and local attenuation coefficients of Rayleigh wave fundamental mode.
The database consists of surface wavetrains recorded at the broadband stations located in the Iberian Peninsula on the occasion
of the ILIHA project. Path-averaged phase and group velocities and attenuation coefficients were previously obtained by standard
filtering techniques of surface wavetrains and, subsequently, local dispersion curves were computed according to the Yanovskaya-Ditmar
formulation. First, a principal component analysis (PCA) and the average linkage (AL) clustering algorithm are applied to
these local values in order to classify the Iberian Peninsula in several rather homogeneous domains from the viewpoint of
the similarity of the corresponding local dispersion curves, without previous seismotectonic constraints. Second, averaged
phase and group velocities and attenuation coefficients representing each homogeneous region are used to derive the respective
elastic and anelastic models of the lithosphere and asthenosphere. This purpose is achieved by using the uncoupled causal
inversion of phase and group velocities and attenuation coefficients. The main features of the homogeneous regions are discussed
by taking as reference the Hercynic, Alpine and Neogene domains of the Iberian Peninsula, and two questions affecting the
reliability of the elastic-anelastic models are revised. First, the coherence of the shear-velocity and Qβ−1 models obtained by causal uncoupled inversion for each region is analysed. Second, the influence of the causal phase and
group velocities on the shear-velocity models is evaluated by comparing elastic and anelastic models derived from causal uncoupled
inversion with those deduced from non-causal inversion. |
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Keywords: | Rayleigh waves tomography clustering algorithms causal uncoupled inversion Iberian Peninsula |
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