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Title: On the Detection of Sharp Upper Mantle Discontinuities with Radon-Transformed Ps Receiver Functions (CRISP-RF)
Seismic interrogation of the upper mantle from the base of the crust to the top of the mantle transition zone has revealed discontinuities that are variable in space, depth, lateral extent, amplitude and lack a unified explanation for their origin. Improved constraints on the detectability and properties of mantle discontinuities (depth, amplitude, sharpness) can be obtained with Ps receiver functions where energy scatters from P to S as seismic waves propagate across discontinuities of interest. However, due to the interference of crustal multiples, uppermost mantle discontinuities are more commonly imaged with lower-resolution Sp-RFs which are not affected by these multiples. Here, we present a novel method for obtaining ‘Clean Receiver-function Imaging using SParse Radon Filters’ (CRISP-RF). The central idea involves the transformation of Ps-RF-data into a Radon-transformed Ps-RF. This approach results in the decomposition of the signal into its underlying wavefield contributions: direct conversions, multiple reflections, and noise. A selective filter is then applied to create multiple-free, denoised, source-deconvolved seismograms. The Radon transform is implemented using a sparsity-promoting regularization, common in disciplines such as compressive sensing and model-based image reconstruction, e.g., optical and microscopic imaging, magnetic resonance imaging, and radar astronomy. We review different algorithms for solving this optimization problem and, based on synthetic and real data, show that our approach outperforms the conventional Tikhonov-regularized least-squares methods. The application of CRISP-RF to global datasets will advance our understanding of the enigmatic origins of the upper mantle discontinuities like the ubiquitous Mid-Lithospheric Discontinuity (MLD), and the elusive X-discontinuity.  more » « less
Award ID(s):
1818654
NSF-PAR ID:
10471819
Author(s) / Creator(s):
Publisher / Repository:
https://essopenarchive.org/doi/full/10.22541/essoar.168614559.90690115
Date Published:
Journal Name:
Geophysical journal international
ISSN:
0956-540X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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