  We present a three-dimensional model describing the propagation of elastic
waves in a soil substrate supporting an array of cylindrical beams experiencing
flexural and compressional resonances. The resulting surface waves are of two
types. In the sagittal plane, hybridized Rayleigh waves can propagate except
within bandgaps resulting from a complex interplay between flexural and
compressional resonances. We exhibit a wave decoupled from the hybridized
Rayleigh wave which is the elastic analogue of electromagnetic spoof plasmon
polaritons. This wave with displacements perpendicular to the sagittal plane is
sensitive only to flexural resonances. Similar, yet quantitatively different,
physics is demonstrated in a two-dimensional setting involving resonances of
plates.
