Stratified Crustal Anisotropy From Receiver Function and Its Particle Swarm Inversion

Abstract

Crustal anisotropy at multiple depths is essential for studying the vertical variation of crustal deformation. Due to the complexity of the crust, mapping the crustal anisotropy at different depth from teleseismic receiver function (RF) is an ongoing subject that requires further studies. Based on the previous works, this paper goes further to discuss the RF wavefield pattern of stratified crustal anisotropy by means of the generalized reflection and transmission coefficients method, which provides us a new theoretical basis for understanding the RF data with stratified anisotropic crustal models. In addition, we develop a global inversion method for extracting stratified anisotropic models based on the particle swarm algorithm. The test results from both numerical and real data show that, our method can correctly recover the depth-dependent anisotropic parameters from the RF data and distinguish different anisotropic layers of the crust, as long as isotropic velocity model is well determined. Noise suppression in data processing via curvelet transform is useful for the analysis of crustal anisotropy.

Crustal Azimuthal Anisotropy Beneath the Southeastern Tibetan Plateau and its Geodynamic Implications

“…For stations with large difference between the two approaches (the difference in 𝜙 is greater than 15 ∘ , or that in 𝛿t is greater than 0.15 s), results from the P m s moveout fitting are used because we have found that this approach usually produces more stable results. This is mostly because the amplitudes of the P m s phase used by the second approach vary more significantly than the arrival times (Han et al, 2017). In addition, the significant trade-off between the crustal anisotropy, tilted axis of symmetry, and dipping interfaces may lead to variations in the stacking amplitude, making it difficult to reliably extract anisotropy using stacking amplitude.…”