The problem of Stoneley waves in a non-homogeneous orthotropic elastic medium under the
influence of gravity was studied recently by Abd-Alla and Ahmed [A.M. Abd-Alla, S.M. Ahmed, Stoneley
waves and Rayleigh waves in a non-homogeneous orthotropic elastic medium under the influence of gravity,
Appl. Math. Comput. 135 (2003) 187-200], who derived the secular equation of the wave in the implicit
form. In this paper, by using an appropriate representation of the solution, we obtain the secular equation of
the wave in the explicit form. Moreover, considering its special cases, we derive explicit secular equations
for a number of investigations of Stoneley waves under the influence of gravity, for which only the implicit
dispersion equations were previously obtained. ?? 2009 Elsevier Inc. All rights reserved.
