On the Detection of Sharp Upper Mantle Discontinuities across North America: Silencing Echoes in the Crust with Sparse Non-linear Radon Filters
Description:
Global maps of upper mantle discontinuities are typically produced using the receiver functions (RF) technique – source-deconvolved seismograms that target seismic structures directly underneath a seismic array. Although the compressional-to-shear receiver function (Ps-RF) technique has been widely successful for crustal imaging, it has seen limited use in continental-scale lithospheric imaging due to signal distortion caused by overprinting of crustal reverberations. For this reason, the shear-to-compressional receiver function (Sp-RF) is usually preferred; even though it produces images with lower frequencies and sparser data sampling. In this study, we obtain sharp images of mantle discontinuities by applying a selective sparse non-linear Radon filter to eliminate crustal reverberations from the Ps-RF. The key idea emphasizes stable decomposition of noisy data-domain RF images into their underlying wavefield contributions in the radon domain by imposing sparsity-promoting constraints. Initial tests using synthetic and data examples from stations CN-ULM and II-RAYN show that sharper and cleaner images of the mantle discontinuities can be obtained without compromising on image resolution. We have compiled waveform data for earthquakes with magnitude >5.5 and epicentral distance between 30º and 90º recorded at TA and all major regional seismic networks in the contiguous US. The proposed method is currently being applied to all ~630,000 events, where we hope to provide improved constraints on the composition, hydration, or change in anisotropic signature that best characterizes seismic discontinuities beneath the contiguous US.
Session: Earth’s Structure From the Crust to the Core [Poster]
Type: Poster
Date: 4/18/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Steve A. B. Carr
Student Presenter: Yes
Invited Presentation:
Authors
Steve Carr Presenting Author Corresponding Author scarr13@ur.rochester.edu University of Rochester |
Tolulope Olugboji tolulope.olugboji@rochester.edu University of Rochester |
Zhang Ziqi zzhang90@ur.rochester.edu University of Rochester |
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On the Detection of Sharp Upper Mantle Discontinuities across North America: Silencing Echoes in the Crust with Sparse Non-linear Radon Filters
Category
Earth’s Structure From the Crust to the Core