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Infragravity waves and horizontal seafloor compliance
Author(s) -
Doran Adrian K.,
Laske Gabi
Publication year - 2016
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2015jb012511
Subject(s) - geology , seismology , seismometer , infragravity wave , seafloor spreading , submarine pipeline , microseism , horizontal and vertical , oceanography , geophysics , geodesy , wave propagation , mechanical wave , longitudinal wave , physics , quantum mechanics
We report the first consistent observation of horizontal seafloor compliance induced by infragravity (IG) waves. Long‐period IG ocean waves manifest themselves as broad, dominant features in ocean bottom pressure and vertical deformation spectra, but signals are rarely (if ever) identified on the horizontal components of traditional ocean bottom seismometers (OBS) due to low signal level and high current‐induced tilt noise at long periods. We examine two OBS stations with shallow‐buried seismometers: the Monterey Ocean Bottom Broadband site offshore California and the Ocean Seismic Network (OSN) pilot site OSN1B near Hawaii. We use nearby weather buoys to investigate the relationship between the presence of infragravity waves and environmental conditions. We find strong evidence that infragravity wave generation is primarily confined to the near‐coastal environment. Additional IG source information is found by examining the directionality of passing IG waves as a function of frequency, which we analyze using the coherence between pressure and the two horizontal components. Finally, we evaluate the implications for a joint vertical and horizontal compliance inversion.