A 3‐D spectral‐element and frequency‐wave number hybrid method for high‐resolution seismic array imaging

Abstract

(2014), A 3-D spectral-element and frequency-wave number hybrid method for high-resolution seismic array imaging, Geophys. Res. Lett., 41, 7025-7034, doi:10.1002 Abstract We present a three-dimensional (3-D) hybrid method that interfaces the spectral-element method (SEM) with the frequency-wave number (FK) technique to model the propagation of teleseismic plane waves beneath seismic arrays. The accuracy of the resulting 3-D SEM-FK hybrid method is benchmarked against semianalytical FK solutions for 1-D models. The accuracy of 2.5-D modeling based on 2-D SEM-FK hybrid method is also investigated through comparisons to this 3-D hybrid method. Synthetic examples for structural models of the Alaska subduction zone and the central Tibet crust show that this method is capable of accurately capturing interactions between incident plane waves and local heterogeneities. This hybrid method presents an essential tool for the receiver function and scattering imaging community to verify and further improve their techniques. These numerical examples also show the promising future of the 3-D SEM-FK hybrid method in high-resolution regional seismic imaging based on waveform inversions of converted/scattered waves recorded by seismic array.

Large‐Scale Seismic Inversion Framework

“…LASIF is independent of the numerical waveform solver, so it is straightforward to integrate, for example, hybrid methods (e.g., Tong et al, 2014) and define additional misfit functionals.…”

Element-by-element parallel spectral-element methods for 3-D teleseismic wave modeling

“…Increasing the model size enables more deep reflections and refractions to be included in the inversion dataset; as a result, deep structures can be inverted by fitting these reflected and refracted waveforms . However, for continental-scale models, it is difficult to invert short-period seismic data on a standard computing cluster, such as 1-2 s for P waves and 3-6 s for S waves (Tong et al, 2015).…”

“…The boundary conditions for the reduced simulation model are provided by rapid 1-D analytical solutions for the 1-D background Earth model (Capdeville et al, 2003;Monteiller et al, 2013Monteiller et al, , 2015Tong et al, 2014aTong et al, , 2015. The 2-D/3-D responses to the heterogeneity inside the reduced model contribute to the coda waves of the teleseismic phases, and the 2-D/3-D effects outside the model are neglected.…”

“…To simplify the teleseismic wave field invariant along a particular axis, the 2.5-D formulation can significantly reduce the computational demands. However, the 2.5-D formulation may restrict the application of the method in arbitrarily heterogeneous media (Tong et al, 2015).…”

“…Tong et al (2015) adapted the Clayton and Engquist-type (CE-type) boundary condition (Clayton and Engquist, 1977) to interface the 1-D background analytical solution with a numerical solver on the boundary of a reduced model. This treatment can both assign the teleseismic incident condition for the computational domain and absorb the scattered wave field from the interior of the heterogeneous model.…”