Open AccessObservations of long period Rayleigh wave ellipticity
Author(s) -
Ferreira Ana M. G.,
Woodhouse John H.
Publication year - 2007
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2006.03276.x
Subject(s) - rayleigh wave , amplitude , geology , seismology , wavelength , rayleigh scattering , tectonics , geodesy , phase velocity , surface wave , seismic wave , phase (matter) , scale (ratio) , period (music) , geophysics , optics , physics , acoustics , quantum mechanics
SUMMARY We analyse phase shifts and amplitude ratios of horizontal to vertical components of T ∼ 150 s fundamental Rayleigh waves. In the ray picture of surface wave propagation, it is expected that at a single station this ratio will be constant, being controlled only by the seismic velocity structure beneath the seismic station. In contrast, we observe substantial variability in the amplitude ratios measured at a number of stations from the Global Seismic Network. We discuss possible causes for the anomalous ratios, concluding that they probably arise from effects associated with small scale heterogeneity distinctly distributed across different tectonic domains and having scale lengths shorter than a wavelength.