In this paper, the influence of magnetic field, gravity field and initial stress on Rayleigh waves propagation in a granular medium under incremental thermal stresses and relaxation times is studied. The frequency equation of Rayleigh waves is obtained in the form of a determinant containing a term involving the coefficient of friction of a granular medium. Some special cases are obtained from this study. Analytically, from the results obtained, one may illustrate that the effect of relaxation times, gravity field, initial stress and magnetic field on Rayleigh wave velocity are very pronounced. It is found that the frequency equation of Rayleigh waves changes with respect to this friction. When the medium is an orthotropic and the magnetic field and friction coefficient vanish, the derived frequency equation reduces to that obtained by Abd-Alla and Ahmed. Relevant results from previous investigations are deduced as special cases of this study.
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