نتایج جستجو برای: rayleigh waves

تعداد نتایج: 126797  

2000
B. Garber M. Cahay G. E. W. Bauer

We study the localization of Rayleigh waves propagating in a semi-infinite and isotropic medium with inhomogeneities that are modeled as rods parallel to the incoming wave front and are distributed randomly up to a maximum depth. For a perfectly smooth surface, the localization length of a Rayleigh wave is predicted to reach a minimum at intermediate wavelength l and to diverge for both low and...

2014
Mohammadi OUAFTOUH Marc DUQUENNOY Julien DEBOUCQ Jean-Etienne LEFEBVRE Frédéric JENOT Mohamed OURAK

In order to control residual stress distribution in glass, techniques based on the phenomenon of photoelasticity are efficient, though subject to the inherent limitations of all optical techniques. To mitigate these limitations, we exploit the phenomenon of acoustoelasticity to estimate residual stress distribution, using surface acoustic waves. In this study, we characterize the surface residu...

2008
Laurette S. Tuckerman

The Boussinesq equations for Rayleigh–Bénard convection are simulated for a cylindrical container with an aspect ratio near 1.5. The transition from an axisymmetric stationary flow to timedependent flows is studied using nonlinear simulations, linear stability analysis and bifurcation theory. At a Rayleigh number near 25000, the axisymmetric flow becomes unstable to standing or travelling azimu...

2005
KATARZYNA BOROŃSKA LAURETTE S. TUCKERMAN

The Boussinesq equations for Rayleigh–Bénard convection are simulated for a cylindrical container with an aspect ratio near 1.5. The transition from an axisymmetric stationary flow to time-dependent flows is studied using nonlinear simulations, linear stability analysis and bifurcation theory. At a Rayleigh number near 25 000, the axisymmetric flow becomes unstable to standing or travelling azi...

2006
Jianghai Xia Yixian Xu Richard D. Miller Jonathan E. Nyquist

Void detection is challenging due to the complexity of near-surface materials and the limited resolution of geophysical methods. Although multichannel, high-frequency, surface-wave techniques can provide reliable shear (S)-wave velocities in different geological settings, they are not suitable for detecting voids directly based on anomalies of the S-wave velocity because of limitations on the r...

1999
Helle A. Pedersen Michel Campillo

Surface waves from the Chinese test site of Lop Nor are analyzed using long-period and broadband stations located at regional and teleseismic distances and at different azimuths. For most azimuths, strong Love waves between 0.02 and 0.04S Hz are observed with an amplitude of up to 10 times that of the Rayleigh waves. In addition, an anomalous early Rayleigh wave train is observed at some statio...

2005
W. S. JARDETZKY FRANK PRESS

THE THEORY of dispersive Rayleigh waves coupled to atmospheric compressional waves is derived for the case of a solid surface layer. Numerical computation of phase and group velocity curves indicates that an additional branch may be introduced to the dispersion curves as a result of air coupling. Amplitudes of waves propagated according to the various branches are briefly discussed. INTRODUCTIO...

2016
Andrea Colombi Daniel Colquitt Philippe Roux Sebastien Guenneau Richard V. Craster

Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear ...

2014
Eric T. Chung Chi Yeung Lam Jianliang Qian

Accurate simulation of Rayleigh waves is of critical importance in a variety of geophysical applications, such as exploration geophysics, geotechnical characterization, and earthquake-related damage assessment. Based on recent works on staggered discontinuous Galerkin methods, we propose for the simulation of Rayleigh waves a new method which enjoys energy conservation and extremely low grid di...

Journal: :فیزیک زمین و فضا 0
مهرداد فتوحی مهر دانشجوی دکتری ژئوفیزیک، مؤسسه ژئوفیزیک دانشگاه تهران، ایران الهام شعبانی استادیار، گروه فیزیک زمین، مؤسسه ژئوفیزیک دانشگاه تهران، ایران نوربخش میرزائی دانشیار، گروه فیزیک زمین، مؤسسه ژئوفیزیک دانشگاه تهران، ایران ابراهیم حق شناس استادیار، پژوهشگاه بین المللی زلز له شناسی و مهندسی زلزله، تهران، ایران

by growing the population and need for settlement, many cities have been built on soft sediments and seismic areas. it emphasizes the need for a careful and reliable assessment of site effect phenomena. beyond the methods of studying site effects, microtremor recordings has become popular over the last decades as it offers a convenient, practical and low cost tool to be used in urbanized areas....

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