Inverse procedure for simultaneous evaluation of viscosity and density of Newtonian liquids from dispersion curves of Love waves

2014 ◽  
Vol 116 (4) ◽  
pp. 044902 ◽  
Author(s):  
P. Kiełczyński ◽  
M. Szalewski ◽  
A. Balcerzak
Keyword(s):  
Dispersion Curves ◽  
Love Waves ◽  
Simultaneous Evaluation ◽  
Newtonian Liquids ◽  
Inverse Procedure

Wave-equation dispersion inversion of Love waves

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. R693-R705 ◽  
Author(s):  
Jing Li ◽  
Sherif Hanafy ◽  
Zhaolun Liu ◽  
Gerard T. Schuster
Keyword(s):  
Wave Equation ◽  
Wave Velocity ◽  
Rayleigh Waves ◽  
Love Wave ◽  
Field Data ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Love Waves ◽  
S Wave ◽  
Love Wave Dispersion

We present a theory for wave-equation inversion of Love-wave dispersion curves, in which the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. Similar to inversion of Rayleigh-wave dispersion curves, the complicated Love-wave arrivals in traces are skeletonized as simpler data, namely, the picked dispersion curves in the [Formula: see text] domain. Numerical solutions to the SH-wave equation and an iterative optimization method are then used to invert these dispersion curves for the S-wave velocity model. This procedure, denoted as wave-equation dispersion inversion of Love waves (LWD), does not require the assumption of a layered model or smooth velocity variations, and it is less prone to the cycle-skipping problems of full-waveform inversion. We demonstrate with synthetic and field data examples that LWD can accurately reconstruct the S-wave velocity distribution in a laterally heterogeneous medium. Compared with Rayleigh waves, inversion of the Love-wave dispersion curves empirically exhibits better convergence properties because they are completely insensitive to the P-velocity variations. In addition, Love-wave dispersion curves for our examples are simpler than those for Rayleigh waves, and they are easier to pick in our field data with a low signal-to-noise ratio.

scholarly journals Ambient Vibration Analysis on Large Scale Arrays When Lateral Variations Occur in the Subsurface: A Study Case in Switzerland

2020 ◽  
Vol 177 (9) ◽  
pp. 4247-4269
Author(s):  
Dario Chieppa ◽  
Manuel Hobiger ◽  
Paolo Bergamo ◽  
Donat Fäh
Keyword(s):  
Wave Velocity ◽  
Vibration Analysis ◽  
Velocity Structure ◽  
Velocity Profiles ◽  
Dispersion Curves ◽  
Love Waves ◽  
Ambient Vibration ◽  
S Wave ◽  
Single Station ◽  
Rayleigh And Love Waves

Abstract The ambient vibration analysis is a non-invasive and low-cost technique used in site characterization studies to reconstruct the subsurface velocity structure. Depending on the goal of the research, the investigated depth ranges from tens to hundreds of meters. In this work, we aimed at investigating the deeper contrasts within the crust and in particular down to the sedimentary-rock basement transition located at thousands of meters of depth. To achieve this goal, three seismic arrays with minimum and maximum interstation distances of 7.9 m and 26.8 km were deployed around the village of Schafisheim. Schafisheim is located in the Swiss Molasse Basin, a sedimentary basin stretching from Lake Constance to Lake Geneva with a thickness ranging from 800 to 900 m in the north to 5 km in the south. To compute the multimodal dispersion curves for Rayleigh and Love waves and the Rayleigh wave ellipticity angles, the data were processed using two single-station and three array processing techniques. A preliminary analysis of the inversion results pointed out a good agreement with the fundamental modes of Rayleigh and Love waves used in the inversion and a quite strong disagreement with the higher modes. The impossibility to explain at the same time most of the dispersion curves was interpreted as the co-existence, within the investigated area, of portions of the subsurface with different geophysical properties. The hypothesis was confirmed by the Horizontal-to-Vertical spectral analysis (H/V) which indicated the presence of two distinguished areas. The observation allowed a new interpretation and the identification of the Rayleigh and Love wave fundamental modes and of the S-wave velocity profiles to be reconstructed for each investigated zone. It results in two S-wave velocity profiles with similar velocities down to 15 km deferring only in their shallow portions due to the occurrence of a low velocity zone at a depth of 50–150 m at the centre of the investigated area.

scholarly journals Love Waves in a Pre-Stressed Fiber-Reinforced Medium Rest upon a Monoclinic Half-Space

2020 ◽  
Vol 9 (3) ◽  
pp. 1680-1685
Keyword(s):  
Dispersion Equation ◽  
Compressive Stress ◽  
Half Space ◽  
Anisotropy Parameter ◽  
Dispersion Curves ◽  
Love Waves ◽  
Initial Stresses ◽  
Tabular Form ◽  
Fiber Reinforced ◽  
Waves Propagation

Love waves in a pre-stressed fiber-reinforced medium lying above a monoclinic half-space have been investigated. Upper surface of fiber reinforced layer remains stress free and interface of half space and layer satisfies continuity conditions .The dispersion equation for Love waves propagation has been derived. Effect of anisotropy parameter of half space and initial stresses of reinforced layer on Love waves propagation have been observed from dispersion curves. Some particular cases have also been developed by using the dispersion equation. Further, the range of the existence of Love waves is calculated. The cut-off periods for three nodes of Love waves with variation of anisotropy parameter and compressive stress are presented in tabular form

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