scholarly journals Repulsion of phase‐velocity dispersion curves and the nature of plate vibrations

1994 ◽  
Vol 96 (2) ◽  
pp. 908-917 ◽  
Author(s):  
H. Überall ◽  
B. Hosten ◽  
M. Deschamps ◽  
A. Gérard
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Dispersion Curves ◽  
Plate Vibrations ◽  
Phase Velocity Dispersion

scholarly journals Repulsion of phase‐velocity dispersion curves and the nature of plate vibrations

1993 ◽  
Vol 94 (3) ◽  
pp. 1877-1877
Author(s):  
B. Hosten ◽  
M. Deschamps ◽  
A. Gérard ◽  
H. Überall
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Dispersion Curves ◽  
Plate Vibrations ◽  
Phase Velocity Dispersion

scholarly journals Repulsion of phase-velocity dispersion curves and the nature of plate vibrations

1994 ◽  
Vol 04 (C5) ◽  
pp. C5-905-C5-908
Author(s):  
M. DESCHAMPS ◽  
B. HOSTEN ◽  
A. GÉRARD ◽  
H. ÜBERALL
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Dispersion Curves ◽  
Plate Vibrations ◽  
Phase Velocity Dispersion

Combining surface-wave phase-velocity dispersion curves and full microtremor horizontal-to-vertical spectral ratio for subsurface sedimentary site characterization

2016 ◽  
Vol 4 (4) ◽  
pp. SQ41-SQ49 ◽  
Author(s):  
Agostiny Marrios Lontsi ◽  
Matthias Ohrnberger ◽  
Frank Krüger ◽  
Francisco José Sánchez-Sesma
Keyword(s):  
Surface Wave ◽  
Phase Velocity ◽  
Velocity Dispersion ◽  
Spectral Ratio ◽  
Test Site ◽  
Dispersion Curves ◽  
Surface Velocity ◽  
Wave Phase ◽  
Phase Velocity Dispersion ◽  
Wave Phase Velocity

We compute seismic velocity profiles by a combined inversion of surface-wave phase-velocity dispersion curves together with the full spectrum of the microtremor horizontal-to-vertical (H/V) spectral ratio at two sediment-covered sites in Germany. The sediment deposits are approximately 100 m thick at the first test site and approximately 400 m thick at the second test site. We have used an extended physical model based on the diffuse wavefield assumption for the interpretation of the observed microtremor H/V spectral ratio. The extension includes the interpretation of the microtremor H/V spectral ratio observed at depth (in boreholes). This full-wavefield approach accounts for the energy contribution from the body and surface waves, and thus it allows for inverting the properties of the shallow subsurface. We have obtained the multimode phase velocity dispersion curves from an independent study, and a description of the extracted branches and their interpretation was developed. The inversion results indicate that the combined approach using seismic ambient noise and actively generated surface-wave data will improve the accuracy of the reconstructed near-surface velocity model, a key step in microzonation, geotechnical engineering, seismic statics corrections, and reservoir imaging.

Shear-wave structure of southern Sweden from precise phase-velocity measurements of ambient-noise data

2020 ◽  
Author(s):  
Hamzeh Sadeghisorkhani ◽  
Ólafur Gudmundsson ◽  
Ka Lok Li ◽  
Ari Tryggvason ◽  
Björn Lund ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Ambient Noise ◽  
Velocity Dispersion ◽  
Dispersion Curves ◽  
Upper Crust ◽  
Southern Sweden ◽  
Zero Crossings ◽  
Phase Velocity Dispersion ◽  
Cross Correlations ◽  
Velocity Bias

Summary Rayleigh-wave phase-velocity tomography of southern Sweden is presented using ambient seismic noise at 36 stations (630 station pairs) of the Swedish National Seismic Network (SNSN). We analyze one year (2012) of continuous recordings to get the first crustal image based on the ambient-noise method in the area. Time-domain cross-correlations of the vertical component between the stations are computed. Phase-velocity dispersion curves are measured in the frequency domain by matching zero crossings of the real spectra of cross-correlations to the zero crossings of the zeroth-order Bessel function of the first kind. We analyze the effect of uneven source distributions on the phase-velocity dispersion curves and correct for the estimated velocity bias before tomography. To estimate the azimuthal source distribution to determine the bias, we perform inversions of amplitudes of cross-correlation envelopes in a number of period ranges. Then, we invert the measured and bias-corrected dispersion curves for phase-velocity maps at periods between 3 and 30 s. In addition, we investigate the effects of phase-velocity bias corrections on the inverted tomographic maps. The difference between bias corrected and uncorrected phase-velocity maps is small ($< 1.2 \%$), but the correction significantly reduces the residual data variance at long periods where the bias is biggest. To obtain a shear velocity model, we invert for a one-dimensional velocity profile at each geographical node. The results show some correlation with surface geology, regional seismicity and gravity anomalies in the upper crust. Below the upper crust, the results agree well with results from other seismological methods.

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