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Global propagation of body waves revealed by cross‐correlation analysis of seismic hum
Author(s) -
Nishida K.
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50269
Subject(s) - geology , seismology , surface wave , geophysics , wave propagation , hum , seismic wave , seismic interferometry , interferometry , love wave , shear (geology) , physics , longitudinal wave , optics , mechanical wave , paleontology , art , performance art , art history
Seismic interferometry has now been applied to the exploration of the Earth's interior at scales ranging from local to global. Most studies have used surface‐wave propagation. Recently, some studies have focused on body wave propagation on local and regional scales but not on a global scale. In this study, we succeed in extracting global body wave propagation(of P , PP , PKP , S , SS , S c S , P ′ P ′ , etc. waves) using seismic hum with frequency‐wave number filtering in the range of 5 to 40 mHz. Although the observed body wave propagation is similar to that of the corresponding components of Green's functions, there are two differences between them: the lack of reflection phases in the observation and the dominance of shear‐coupled PL waves in the observation. These differences originate from the dominance of shear‐traction sources on the Earth's surface, which causes the breakdown of equipartition among modes with different radial orders. For further studies of body wave exploration by seismic interferometry, these differences should be considered.