Effects of irregular topography on Rayleigh-wave propagation in surface-wave exploration

Purpose The purpose of study to this article is to analyze the Rayleigh wave propagation in an isotropic dry sandy thermoelastic half-space. Various wave characteristics, i.e wave velocity, penetration depth and temperature have been derived and represented graphically. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Design/methodology/approach The present article deals with the propagation of Rayleigh surface wave in a homogeneous, dry sandy thermoelastic half-space. The dispersion equation for the proposed model is derived in closed form and computed analytically. The velocity of Rayleigh surface wave is discussed through graphs. Phase velocity and penetration depth of generated quasi P, quasi SH wave, and thermal mode wave is computed mathematically and analyzed graphically. To illustrate the analytical developments, some particular cases are deliberated, which agrees with the classical equation of Rayleigh waves. Findings The dispersion equation of Rayleigh waves in the presence of thermal conductivity for a dry sandy thermoelastic medium has been derived. The dry sandiness parameter plays an effective role in thermoelastic media, especially with respect to the reference temperature for η = 0.6,0.8,1. The significant difference in η changes a lot in thermal parameters that are obvious from graphs. The penetration depth and phase velocity for generated quasi-wave is deduced due to the propagation of Rayleigh wave. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Originality/value Rayleigh surface wave propagation in dry sandy thermoelastic medium has not been attempted so far. In the present investigation, the propagation of Rayleigh waves in dry sandy thermoelastic half-space has been considered. This study will find its applications in the design of surface acoustic wave devices, earthquake engineering structural mechanics and damages in the characterization of materials.

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Rayleigh Wave Propagation in the Bighorn Mountains Region, Wyoming

Bulletin of the Seismological Society of America ◽

10.1785/0120210116 ◽

2021 ◽

Author(s):

Jonas A. Kintner ◽

K. Michael Cleveland ◽

Ryan Modrak ◽

Audrey Dunham

Keyword(s):

Wave Propagation ◽

Surface Wave ◽

Rayleigh Wave ◽

Rayleigh Waves ◽

Sedimentary Basins ◽

Near Surface ◽

Retrograde Motion ◽

Explosion Monitoring ◽

Short Period ◽

Surface Geology

ABSTRACT Short-period Rayleigh waves, Rg, provide strong constraints on the depth of shallow seismic events and are of interest for monitoring small explosions. Characterizing the seismic sources that generate Rg requires an understanding of how shallow crustal structure affects Rayleigh wave propagation. In support of these efforts, this study utilizes observed waveforms from small shallow explosions recorded on temporary seismic network deployments in the Bighorn region, Wyoming. We study regional near-surface geology by measuring changes in surface-wave amplitude and polarization during propagation through basins, foothills, and mountains. We develop additional insight by carrying out surface-wave eigenfunction analyses and numerical-wave simulations, which together reproduce many characteristics seen in the observed waveforms. Our results show how sedimentary basins in the Bighorn region allow for amplified prograde-polarized higher-mode and retrograde-polarized fundamental-mode Rayleigh waves, whereas adjacent mountains only support retrograde motion. These different modes provide distinct constraints on the Earth structure and source characteristics, potentially enabling targeted inversions in future studies. Our findings provide insight into Rg propagation through complex near-surface geology, improving our understanding of shallow propagation and source effects that are relevant to explosion monitoring efforts.

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RAYLEIGH WAVE TRANSMISSION ON ELASTIC WEDGES

Geophysics ◽

10.1190/1.1439260 ◽

1963 ◽

Vol 28 (5) ◽

pp. 715-723 ◽

Cited By ~ 19

Author(s):

J. Kane ◽

J. Spence

Keyword(s):

Experimental Data ◽

Wave Propagation ◽

Surface Wave ◽

Rayleigh Wave ◽

Wedge Angle ◽

Numerical Data ◽

Iteration Procedure ◽

Free Boundaries ◽

Conversion Coefficients ◽

Leading Term

A method is introduced by which transmission or conversion coefficients can readily be calculated for surface‐wave action at crustal discontinuities which can be idealized as wedge‐shaped obstacles. The method, an iteration procedure, is illustrated by an application to Rayleigh‐wave propagation on elastic wedges with free boundaries. It is shown that the leading term of the iteration procedure yields an expression for the transmission coefficient which matches the experimental data for a range of wedge angles which includes the crustal wedges commonly found in seismic practice. Numerical data are presented which illustrate the transmission coefficient’s variation in terms of Poisson’s ratio and the wedge angle.

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Guided Surface Waves on an Elastic Half Space

Journal of Applied Mechanics ◽

10.1115/1.3408973 ◽

1971 ◽

Vol 38 (4) ◽

pp. 899-905 ◽

Cited By ~ 5

Author(s):

L. B. Freund

Keyword(s):

Wave Propagation ◽

Surface Wave ◽

Surface Waves ◽

Half Space ◽

Body Wave ◽

Three Dimensional ◽

Elastic Half Space ◽

Normal Displacement ◽

Rigid Barrier ◽

Wave Disturbances

Three-dimensional wave propagation in an elastic half space is considered. The half space is traction free on half its boundary, while the remaining part of the boundary is free of shear traction and is constrained against normal displacement by a smooth, rigid barrier. A time-harmonic surface wave, traveling on the traction free part of the surface, is obliquely incident on the edge of the barrier. The amplitude and the phase of the resulting reflected surface wave are determined by means of Laplace transform methods and the Wiener-Hopf technique. Wave propagation in an elastic half space in contact with two rigid, smooth barriers is then considered. The barriers are arranged so that a strip on the surface of uniform width is traction free, which forms a wave guide for surface waves. Results of the surface wave reflection problem are then used to geometrically construct dispersion relations for the propagation of unattenuated guided surface waves in the guiding structure. The rate of decay of body wave disturbances, localized near the edges of the guide, is discussed.

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