Deep structure of the Bohemian Massif from phase velocities of Rayleigh and Love waves

Wielandt, Erhard; Ples̆inger, A.; Sigg, Andreas; Horálek, Josef

doi:10.1016/0031-9201(88)90036-2

Cited by 7 publications

(3 citation statements)

References 8 publications

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“…As starting model we used an average 1D Mediterranean velocity model [ Marone et al , 2004]. This procedure produces neither a pure SV ‐ nor SH ‐velocity model [ Kirkwood , 1978], but is suitable [ Wielandt et al , 1987] for a first order estimate of the required SH / SV velocity difference.…”

Section: D Sh‐ and Sv‐velocity Modelsmentioning

confidence: 99%

Shallow anisotropy in the Mediterranean mantle from surface waves

Marone

Lee

Giardini³

2004

Geophysical Research Letters

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[1] We present new evidence for the existence of the LoveRayleigh discrepancy in the Mediterranean region and constrain the average polarization anisotropic structure of the Mediterranean mantle. We analysed regional Rayleigh and Love waveforms recorded at 3-component broadband seismic stations. None of the 3-component seismograms could be fit with a single 1D isotropic and smooth velocity model. However, satisfactory fits for individual Rayleigh and Love waveforms could often be obtained using realistic 1D velocity models. We used these 1D path-average velocity structures to derive 3D S-velocity models for the Mediterranean region. Our results show that Love waves require higher velocities (about 200 m/s) compared to Rayleigh waves between 30 and 120 km depth. We relate the observed anisotropy to lattice-preferred orientation of crystallographic axes of elastically anisotropic minerals such as olivine.

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Section: D Sh‐ and Sv‐velocity Modelsmentioning

confidence: 99%

Shallow anisotropy in the Mediterranean mantle from surface waves

Marone

Lee

Giardini³

2004

Geophysical Research Letters

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“…It has, however, to be large enough to be representative of a random structure, and to ensure that wave phenomena such as wave front healing converge sufficiently. Significant Love–Rayleigh discrepancies have been observed by interstation phase measurements over regions which are not more than a few hundred kilometres wide (Wielandt et al 1987; Friederich & Huang 1996; Maupin & Cara 1992; Freybourger et al 2001). Measuring apparent phase velocity over a distance of 1000 km should therefore be sufficient to test if this observed discrepancy is biased by small‐scale heterogeneities.…”

Section: Characteristics Of the Modelsmentioning

confidence: 99%

The amplitude of the Love-Rayleigh discrepancy created by small-scale heterogeneities

Maupin¹

2002

Geophysical Journal International

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Summary At global as well as at regional scale, the lithosphere appears faster to Love waves than to Rayleigh waves. This Love–Rayleigh discrepancy can be modelled by introducing transverse isotropy in the upper mantle. In some regions however, it is so large that the question arises as to whether part of it could be an artefact related to the presence of heterogeneities in the lithosphere. Using a multiple‐scattering scheme to model surface waves in 3‐D structures, we analyse the influence of small‐scale heterogeneities in the lithosphere on the Love–Rayleigh discrepancy in the period range 25 to 60 s. Small‐scale heterogeneities tend to lower the apparent phase velocity of the surface waves, and have a larger effect on the Love waves than on the Rayleigh waves. This is not due to mode‐coupling, which plays a negligible role here, but to the interference of the primary field with the one backscattered twice. For models with S‐wave velocity variations of rms 2.5 per cent, and spatial correlations at distances of 20 to 100 km, we find that the Love waves are on average and at most 0.1 per cent slower than the Rayleigh waves. This apparent Love–Rayleigh discrepancy varies linearly with the variance of S‐wave velocity variation in the structure. We conclude that small‐scale heterogeneities do not contribute significantly to the large Love–Rayleigh discrepancies of 4 to 9 per cent observed in some regions, since they produce an apparent discrepancy which is negligible in comparison, and which even has the opposite sign.

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“…Cara et al [19_80], Wielandt et al [1987] and Maupin and Cara [1992] in the European mantle, and e.g. Cara et al [19_80], Wielandt et al [1987] and Maupin and Cara [1992] in the European mantle, and e.g.…”

Section: Introductionmentioning

confidence: 99%

Evidence for upper mantle anisotropy beneath southern Germany from Love and Rayleigh wave dispersion

Friederich

Huang

1996

Geophysical Research Letters

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We advance evidence for the existence of seismic anisotropy in the upper mantle beneath Southern Germany from the dispersion of Love and Rayleigh waves. The evidence is based upon a substantial Love‐Rayleigh discrepancy observed between periods of 40 s and 120 s. An isotropic mantle model clearly fails to explain the observed dispersion curves. Systematic inversion experiments with transversely isotropic models show that anisotropy at depths between 70 km and 200 km is sufficient to explain the observed dispersion curves. Our data require neither anisotropy at greater depths nor anisotropy in the crust though we cannot exclude its presence there. A search for azimuthal anisotropy of Rayleigh wave propagation indicates a weak, but possibly insignifant azimuthal anisotropy of about 1% for periods less than 40 s with fast directions between 20 and 50 degrees east of north. At larger periods azimuthal anisotropy is less than 1% and the fast directions scatter considerably as period varies.

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Deep structure of the Bohemian Massif from phase velocities of Rayleigh and Love waves

Cited by 7 publications

References 8 publications

Shallow anisotropy in the Mediterranean mantle from surface waves

Shallow anisotropy in the Mediterranean mantle from surface waves

The amplitude of the Love-Rayleigh discrepancy created by small-scale heterogeneities

Evidence for upper mantle anisotropy beneath southern Germany from Love and Rayleigh wave dispersion

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