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1
Reflection and refraction of quasi-SV waves at the interface of the monoclinic media
100%
Chattopadhyay A. , Saha S.
Acta Geophysica Polonica
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1999
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tom Vol. 47, nr 3
307-322
EN
Reflection and refraction phenomena of quasi-SV waves at a plane interface of two monoclinic half-spaces have been discussed. It has been pointed out that due to incident quasi-SV wave in a monoclinic medium, the three types of waves exist: quasi-P (qP), quasi-SV (qSV) and quasi-SH (qSH). The reflection and refraction coefficients for qP, qSV and qSH waves have been computed. The effects due to the crystalline nature of the medium have been distinctly marked. The results are presented graphically and compared with the isotropic case.
2
Content available remote Reflection and refraction of waves at the interface of an isotropic medium over a highly anisotropic medium
100%
Chattopadhyay A. , Rajneesh H.
Acta Geophysica
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2006
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tom Vol. 54, no. 3
239-249
EN
In this paper, we have considered the reflection and refraction of a plane wave at an interface between two half-spaces. The lower half-spaces is composed of highly anisotropic triclinic crystalline material and the upper half-space is homogeneous and isotropic. It has been assumed that due to incidence of a plane quasi-P (qP) wave, three types of waves, namely, quasi-P (qP), quasi-SV (qSV) and quasi-SH (qSH), will be generated in the lower half space whereas P and S waves will be generated in the upper half space. The phase velocities of all the quasi waves have been calculated. It has been assumed that the direction of particle motion is neither parallel nor perpendicular to the direction of propagation. Some specific relations have been established between directions of motion and propagation, respectively. The expressions for reflection coefficients of qP, qSV, qSH and refracted coeffi-cients of P and SV waves are obtained. Results of reflection and refraction coeffi-cients are presented.
3
Content available remote Propagation of shear waves in viscoelastic medium at irregular boundaries
80%
Chattopadhyay A. , Gupta S. , Sharma V. K. , Kumari P.
Acta Geophysica
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2010
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tom Vol. 58, no. 2
196-214
EN
The aim of the paper is to study the shear wave propagation in a viscoelastic layer over a semi-infinite viscoelastic half space due to irregularity in the viscoelastic layer. It is of great interest to study the propaga-tion of shear waves in the assumed medium having a non planar boundary due to its similarity to most of the real situations. The perturbation method is applied to find the displacement field. The effect of complex wave number on dissipation factor is analysed. Finally, as an application, the result obtained has been used to get the reflected field in viscoelastic layer when the shear wave is incident on an irregular boundary in the shape of parabolic irregularity as well as triangular notch. It is observed that the amplitude of this reflected wave decreases with increasing length of the notch, and increases with increasing depth of the irregularity.
4
Content available remote Effect of Corrugation and Reinforcement on the Dispersion of SH-wave Propagation in Corrugated Poroelastic Layer Lying over a Fibre-reinforced Half-space
80%
Singh A. K. , Das A. , Lakshman A. , Chattopadhyay A.
Acta Geophysica
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2016
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tom Vol. 64, no. 5
1340--1369
EN
The presence of porosity and reinforcement in a medium is an important factor affecting seismic wave propagation and plays vital role in many geophysical prospects. Also, the presence of salt and ore deposits, mountains, basins, mountain roots, etc. is responsible for the existence of corrugated boundary surfaces of constituent layers. Such facts brought motivation for the present paper which deals with the propagation of SHwave in a heterogeneous fluid-saturated poroelastic layer with corrugated boundaries lying over an initially stressed fibre-reinforced elastic halfspace. Closed form of dispersion relation has been obtained and is found in well agreement to classical Love wave equation for isotropic case. The effect of corrugation, wave number, undulation, position parameter, horizontal compressive/tensile initial stress and heterogeneity on phase velocity has been analysed through numerical computation and graphical illustration. Moreover, comparative study exploring the effect of presence and absence of reinforcement in half-space on dispersion curve is the major highlight of the current study.
5
Content available remote Impact of Inhomogeneity on SH-type Wave Propagation in an Initially Stressed Composite Structure
80%
Saha S. , Chattopadhyay A. , Singh A. K.
Acta Geophysica
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2018
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tom Vol. 66, no. 1
1--19
EN
The present analysis has been made on the influence of distinct form of inhomogeneity in a composite structure comprised of double superficial layers lying over a half-space, on the phase velocity of SH-type wave propagating through it. Propagation of SH-type wave in the said structure has been examined in four distinct cases of inhomogeneity viz. when inhomogeneity in double superficial layer is due to exponential variation in density only (Case I); when inhomogeneity in double superficial layers is due to exponential variation in rigidity only (Case II); when inhomogeneity in double superficial layer is due to exponential variation in rigidity, density and initial stress (Case III) and when inhomogeneity in double superficial layer is due to linear variation in rigidity, density and initial stress (Case IV). Closed-form expression of dispersion relation has been accomplished for all four aforementioned cases through extensive application of Debye asymptotic analysis. Deduced dispersion relations for all the cases are found in well-agreement to the classical Love-wave equation. Numerical computation has been carried out to graphically demonstrate the effect of inhomogeneity parameters, initial stress parameters as well as width ratio associated with double superficial layers in the composite structure for each of the four aforesaid cases on dispersion curve. Meticulous examination of distinct cases of inhomogeneity and initial stress in context of considered problem has been carried out with detailed analysis in a comparative approach.
6
Characterization of genetic resources and Identification of selection Indices of brinjal (Solanum melongena L.) grown in eastern India
80%
Chattopadhyay A. , Dutta S. , Hazra P.
Vegetable Crops Research Bulletin
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2011
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tom 74
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