Are Deep - Ocean - Generated Surface - Wave Microseisms Observed on 1 Land ?

6 Recent studies attribute land double-frequency (DF) microseism observations to deep7 water generation. Here we show that near-coastal generation is generally the dominant 8 source region. This determination is based on observations at land and ocean seismic 9 stations, buoys, gravity wave hindcasts, and on beamforming results from continental 10 seismic arrays. Interactions between opposing ocean wave components generate a 11 pressure excitation pulse at twice the ocean wave frequency that excites pseudo12 Rayleigh (pRg) wave DF microseisms. pRg generated in shallow coastal waters have 13 most of their energy in the solid Earth (“elastic” pRg) and are observed by land-based 14 and seafloor seismometers as DF microseisms. pRg generated in the deep-ocean have 15 most of their energy in the ocean (“acoustic” pRg) and are continuously observed on the 16 ocean-bottom, but acoustic pRg does not efficiently transition onto continents. High 17 amplitude DF signals over the [0.2,0.3] Hz band observed on the deep seafloor are 18 uncorrelated with continental observations, and are not clearly detectable at individual 19 continental stations or by land seismic-array beamforming. Below 0.2 Hz, modeling and 20 some observations suggest that some deep-water-generated elastic pRg energy can reach 21 continental stations, providing that losses from scattering and transition across the 22 continental-shelf boundary to the shore are not substantial. However, most observations 23 indicate that generally little deep-ocean-generated DF microseism energy reaches 24 continental stations. Effectively, DF land observations are dominated by near-coastal 25 wave activity. 26