Microseisms: A twenty-six-second spectral line in long-period earth motion

A narrow-band microseismic peak exists in worldwide earth background near a period of 26 sec. During storms, the amplitude of this ground motion increases to high levels which allows detailed studies of its characteristics. Analysis indicates that the energy arrives as Rayleigh waves from a source in the southern Atlantic Ocean. The most significant property of this microseismic peak is that it is nondispersive, thereby eliminating deep-water ocean-wave dispersion as the mechanism for isolating the narrow-band energy.