A Generalized Strategy From S‐Wave Receiver Functions Reveals Distinct Lateral Variations of Lithospheric Thickness in Southeastern Tibet

Abstract

AbstractThe selected rotation angle and deconvolution time window during S‐wave receiver function (SRF) calculations, and the final SRF quality control may introduce artificial interference. Here we overcome these problems by proposing a new strategy named GC_SRF for obtaining the lithospheric thickness from S‐wave receiver functions, which employs grid search and correlation analysis to obtain reliable SRFs. Extensive tests using synthetic and real data suggest that the GC_SRF strategy is a robust and reproducible approach for estimating lithospheric thickness. Specifically, this GC_SRF strategy can restore the weak Sp phases from full wavefield synthetic seismograms. Clear and distinct discontinuity patterns that do not involve artificial interference compared with those obtained in previous studies of southeastern Tibet are produced here. The post‐stack migrated SRFs reveal distinct lateral variations of lithospheric thickness in southeastern Tibet: (a) Tengchong volcano has a thin crust and thin lithosphere–asthenosphere boundary (LAB) (∼90 km); (b) the Chuandian region has a thicker crust and either a poorly defined or unclear LAB. The absence of a continuous LAB in the Chuandian region may suggest lithospheric regrowth due to the recovery processes of the mantle plume; (c) a thinner crust and clear LAB of ∼160 km depth is presented beneath the Sichuan Basin.