Phase velocity maps of Rayleigh waves in the Ordos block and adjacent regions

2018 ◽  
Vol 31 (5-6) ◽  
pp. 234-241
Author(s):  
Shaoxing Hui ◽  
◽  
Wenhua Yan ◽  
Yifei Xu ◽  
Liping Fan ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Rayleigh Waves ◽  
Ordos Block

scholarly journals The Complex Rayleigh Waves in a Functionally Graded Piezoelectric Half-Space: An Improvement of the Laguerre Polynomial Approach

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2320 ◽  
Author(s):  
Ke Li ◽  
Shuangxi Jing ◽  
Jiangong Yu ◽  
Xiaoming Zhang ◽  
Bo Zhang
Keyword(s):  
Phase Velocity ◽  
Half Space ◽  
Rayleigh Waves ◽  
Three Dimensional ◽  
Wave Mode ◽  
Functionally Graded ◽  
Function Technique ◽  
Complex Wave ◽  
Acoustic Wave Devices ◽  
Functionally Graded Piezoelectric

The research on the propagation of surface waves has received considerable attention in order to improve the efficiency and natural life of the surface acoustic wave devices, but the investigation on complex Rayleigh waves in functionally graded piezoelectric material (FGPM) is quite limited. In this paper, an improved Laguerre orthogonal function technique is presented to solve the problem of the complex Rayleigh waves in an FGPM half-space, which can obtain not only the solution of purely real values but also that of purely imaginary and complex values. The three-dimensional dispersion curves are generated in complex space to explore the influence of the gradient coefficients. The displacement amplitude distributions are plotted to investigate the conversion process from complex wave mode to propagating wave mode. Finally, the curves of phase velocity to the ratio of wave loss decrements are illustrated, which offers extra convenience for finding the high phase velocity points where the complex wave loss is near zero.

Analysis of gravity and non-homogeneity on Rayleigh wave in anisotropic elastic-viscoelastic half space of higher order

2015 ◽  
Vol 11 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Rajneesh Kakar
Keyword(s):  
Phase Velocity ◽  
Half Space ◽  
Rayleigh Waves ◽  
Mass Density ◽  
Wave Number ◽  
Inhomogeneous Layer ◽  
Third Order ◽  
Content Type ◽  
Anisotropic Elastic ◽  
Mathematical Techniques

Purpose – The purpose of this paper is to illustrate the propagation of Rayleigh waves in an anisotropic inhomogeneous layer placed over an isotropic gravitational viscoelastic half space of third order. Design/methodology/approach – It is considered that the mass density and the elastic coefficients of the layer are space dependent. Dispersion properties of waves are derived with the simple mathematical techniques. Graphs are plotted between phase velocity ‘k’ and wave number ‘c’ for different values of inhomogeneity parameters for a particular model and the effects of inhomogeneity and gravity are studied. Findings – The wave analysis indicates that the phase velocity of Rayleigh waves is affected quite remarkably by the presence of inhomogeneity, gravity and strain rates of strain parameters in the half space. The effects of inhomogeneity and depth on the phase velocity are also shown in corresponding figures. Originality/value – The results presented in this study may be attractive and useful for mathematicians, seismologists and geologists.

Propagation of Cylindrical Rayleigh Waves in a Transversly Isotropic Thermoelastic Diffusive Solid Half-Space

2013 ◽  
Vol 43 (3) ◽  
pp. 3-20 ◽  
Author(s):  
Rajneesh Kumar ◽  
Tarun Kansal
Keyword(s):  
Phase Velocity ◽  
Boundary Conditions ◽  
Dispersion Equation ◽  
Half Space ◽  
Rayleigh Waves ◽  
Attenuation Coefficients ◽  
Special Cases ◽  
Phase Velocity And Attenuation

Abstract The propagation of cylindrical Rayleigh waves in a trans- versely isotropic thermoelastic diffusive solid half-space subjected to stress free, isothermal/insulated and impermeable or isoconcentrated boundary conditions is investigated in the framework of different theories of ther- moelastic diffusion. The dispersion equation of cylindrical Rayleigh waves has been derived. The phase velocity and attenuation coefficients have been computed from the dispersion equation by using Muller’s method. Some special cases of dispersion equation are also deduced

scholarly journals Unusual, equivocal Rayleigh-dispersion curves for simple models taking into account the special propagation conditions in the valley of Mexico City (CDMX) - Preliminary results

2017 ◽  
Vol 56 (1) ◽  
Author(s):  
Peter G. Malischewsky ◽  
Thomas Forbriger ◽  
Cinna Lomnitz†
Keyword(s):  
Phase Velocity ◽  
Mexico City ◽  
Rayleigh Waves ◽  
Poisson’S Ratio ◽  
Dispersion Analysis ◽  
Poisson's Ratio ◽  
Homogeneous Layer ◽  
Preliminary Results ◽  
Analysis And Synthesis ◽  
Simple Models

Other than commonly assumed in seismology, the phase velocity of Rayleigh waves not necessarily is a single-valued function of frequency. We demonstrate this for the first higher mode in simple models of a homogeneous layer on top of a homogeneous halfspace (LOH), which are used for the subsurface of the Texcoco zone in Mexico City valley in previous studies. In the structure of a homegenous layer with fixed bottom (LFB) the phenomenon exists for values of Poisson’s ratio between 0.19 and 0.5 and is most pronounced for P-velocity being three times S-velocity (Poisson’s ratio of 0.4375). This type of dispersion is demonstrated and a discussion of their possible fatal consequences for methods customarily used in seismology for dispersion analysis and synthesis of dispersion relations is presented.

scholarly journals Spheroidal free periods of the earth observed at eight stations around the world

1964 ◽  
Vol 54 (2) ◽  
pp. 755-776
Author(s):  
L. E. Alsop
Keyword(s):  
Phase Velocity ◽  
Rayleigh Waves ◽  
Vertical Motion ◽  
Present Theory ◽  
Period Range ◽  
Moving Source ◽  
The Earth ◽  
Spectral Peaks ◽  
The World ◽  
Different Parts

ABSTRACT Spectral peaks corresponding to the spheroidal free periods of oscillation of the earth exist in the spectra of eight seismograms written at stations in different parts of the world shortly after the great Chilean earthquake of 22 May 1960. These data have been combined with those previously reported by various authors to obtain a very precise phase velocity vs period curve for Rayleigh waves in the period range of 200 to 3200 seconds. The observed spectral amplitudes lend some support to the assumption of a moving source, but they also indicate that the present theory is not adequate. The vertical motion is found to be symmetric with respect to reflections through the pole.

Reflection and transmission of obliquely incident Rayleigh waves at a vertical discontinuity between two welded quarter-spaces

1979 ◽  
Vol 69 (5) ◽  
pp. 1409-1423
Author(s):  
Thomas C. Chen ◽  
Leonard E. Alsop
Keyword(s):  
Free Surface ◽  
Phase Velocity ◽  
Rayleigh Waves ◽  
Velocity Ratio ◽  
Normal Incidence ◽  
Angle Of Incidence ◽  
Reflection And Transmission ◽  
Obliquely Incident ◽  
Vertical Boundary ◽  
Diffraction Effects

abstract We use an approximate method to study the reflection and transmission of obliquely incident Rayleigh waves on a vertical boundary between two welded quarter-spaces. For two media with a phase velocity ratio of 1.16 our calculation shows that the transmitted energy follows a reciprocity relation and decreases from near 100 per cent at normal incidence to 50 per cent at about 40°. The reflected energy is less than 1 per cent for angles of reflection less than 40°. When the Rayleigh wave impinges upon the less rigid medium, the reflected energy decreases as the angle of incidence increases; whereas for incidence at the more rigid medium, the reflected energy decreases at first, and then it increases as the angle of incidence increases. Since boundary conditions on the free surface are not taken into account by our method, diffraction effects are ignored. The effect of neglecting the free surface requirement is difficult to quantify, but we believe that it is small since the calcualted and experimental results agree well at normal incidence.

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