Comparison of ocean-wave and microseism spectrums as recorded at Barbados, West Indies

Power spectrums computed from recordings of ocean waves and microseisms made at Barbados, West Indies, are compared. The ocean-wave spectrums show abrupt onsets of waves having energy peaks in the low-frequency end of the spectrum which can be compared with the onset of energy peaks in the low-frequency end of the microseism spectrums, but at a frequency double that of the ocean waves. A delay of 18 to 24 hours is observed between the onset of the ocean waves and the corresponding development of energy in the microseism spectrums which may be attributable to the time required to develop an interfering wave pattern in the vicinity of the island, this interference giving rise to the generation of microseisms in accordance with the Longuet-Higgins theory. A linear increase with time in the frequency of the peak energy in the ocean-wave spectrums is observed; it is consistent with the increase expected by the dispersive propagation of ocean waves over the ocean.