Multimode Rayleigh wave inversion for heterogeneity and azimuthal anisotropy of the Australian upper mantle

Lateral Heterogeneity and Azimuthal Anisotropy of the Upper Mantle: Love and Rayleigh Waves 100-250 s

The lateral heterogeneity and apparent anisotropy of the upper mantle are studied by measuring Rayleigh and Love wave phase velocities in the period range 100-250 s. Spherical harmonic descriptions of the lateral heterogeneity are obtained for order and degree up to 1 = m = 10. Slow regions are evident at the East Pacific Rise, northeast Africa, Tibet, Tasman Sea, southwestern North America, an...

Inversion of teleseismic S particle motion for azimuthal anisotropy in the upper mantle: a feasibility study

We have developed a technique for the inversion of teleseismic S-waveforms in terms of azimuthal anisotropy in the upper mantle. We test different models of the Earth upper mantle by transforming the observed horizontal components into a synthetic vertical component and comparing this with the observed vertical component. The optimum model is found by minimizing the difference between the synth...

Depth dependent azimuthal anisotropy in the western US upper mantle

Upper crustal azimuthal anisotropy across the contiguous U.S. determined by Rayleigh wave ellipticity

Constraints on upper crustal seismic anisotropy provide insight into the local stress orientation and structural fabric, but such constraints are scarce except in areas with dense recordings of local seismicity. We investigate directionally dependent Rayleigh wave ellipticity, or Rayleigh wave H/V (horizontal to vertical) amplitude ratios, between 8 and 20 s period across USArray to infer azimu...

New constraints on the upper mantle structure of the Slave craton from Rayleigh wave inversion

[1] Rayleigh wave phase and amplitude data are analyzed to provide new insight into the velocity structure of the upper mantle beneath the Slave craton, in the northwestern Canadian Shield. We invert for phase velocities at periods between 20 s–142 s (with greatest sensitivity at depths of 28–200 km) using crossing ray paths from events recorded by the POLARIS broadband seismic network and the ...