The Characteristics of Rayleigh and Love Wave Azimuthal Anisotropy: Observations Across Alaska | CU Experts

Abstract; Using ambient noise data from 10 to 50 s period across Alaska, we confirm previous estimates of Rayleigh wave 2 azimuthal anisotropy and present the first estimates of Rayleigh wave 4 and Love wave 2 and 4 azimuthal anisotropy, where is the angle of propagation. As in earlier studies, the fast orientations of Rayleigh wave 2 are mainly parallel to major faults in Alaska at all periods. We also find that on average the fast orientations of Love wave 4 are rotated 45° relative to Rayleigh wave 2, the fast orientation of Rayleigh wave 4 aligns with Love wave 2, and the fast orientation differences of Rayleigh and Love wave 2 range between 0° and 90° with many between 40° to 60°. These observations are consistent with non‐elliptical anisotropy with the ellipticity parameters and considerably smaller than 1. Observations of Love wave 2 and Rayleigh wave 4 reflect strong Rayleigh‐Love coupling, which causes the observed complementary trends with period of the amplitudes of Rayleigh and Love wave 2 and Rayleigh and Love wave 4 Recent theories of Rayleigh‐Love coupling based on a quasi‐degenerate theory allow these observations to be understood and to be used in the future to improve models of the elastic tensor in the crust and mantle.

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