Open AccessA source of significant transverse arrivals from an isotropicanisotropic interface, e.g. the Moho
Author(s) -
Guest W. S.,
Thomson C. J.
Publication year - 1992
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.1992.tb00579.x
Subject(s) - transverse plane , isotropy , anisotropy , longitudinal wave , amplitude , transverse wave , refraction , physics , wave propagation , s wave , optics , geophysics , structural engineering , engineering
SUMMARY When a P ‐wave is incident on an isotropic‐anisotropic boundary, the reflected S conversion will generally contain some transverse ( SH ) component. Numerical results show that the magnitude of this SH component is strongly related to the transmitted qP ‐wave and the form of the P ‐wave anisotropy (degree and orientation) in the lower medium, rather than the jump in shear wave velocities over the interface. Varying Poisson's ratio in the incident medium changes the amplitude of the reflected SV component, as one would expect, but has minimal effect on the reflected SH signal. Therefore, it is possible to obtain reflected S ‐waves that are almost purely transverse, even though the source is compressional and the medium of propagation is isotropic. This study of these indirect effects of anisotropy was prompted by anomalous transverse signals in a refraction data set, which is included for comparison.