We investigate asymptotic equations describing small amplitude surface elas
tic waves in the half-plane (Rayleigh waves). For hyperelastic materials su
ch model equations are Hamiltonian systems, and are seen to lead to the for
mation of singularities in the surface elastic displacement. At the time of
singularity formation the Fourier spectra of the solutions exhibit power l
aw decay, and the observed exponents suggest the existence of both differen
tiable and non-differentiable singular profiles. (C) 2001 Elsevier Science
B.V. All rights reserved.