Thorne, M, Leng, K, Pachhai, S et al. (3 more authors) (2021) The most parsimonious ultralow‐velocity zone distribution from highly anomalous SPdKS waveforms. Geochemistry, Geophysics, Geosystems, 22 (1). e2020GC009467. ISSN 1525-2027
Abstract
The locations of ultralow‐velocity zones (ULVZs) at the core‐mantle boundary (CMB) have been linked to a variety of features including hot spot volcanoes and large low‐velocity province (LLVP) boundaries, yet only a small portion of the CMB region has been probed for ULVZ existence. Here we present a new map of lower mantle heterogeneity locations using a global collection of highly anomalous SPdKS recordings based on a dataset of more than 58,000 radial component seismograms, which sample 56.9% of the CMB by surface area. The inference of heterogeneity location using the SPdKS seismic phase is challenging due to source‐versus receiver‐side ambiguity. Due to this ambiguity, we conducted an inversion using the principle of parsimony. The inversion is conducted using a genetic algorithm which is repeated several thousand times in order to construct heterogeneity probability maps. This analysis reveals that at probabilities urn:x-wiley:15252027:media:ggge22404:ggge22404-math-00010.5, 0.25, and 0.125 up to 1.3%, 8.2%, or 19.7% of the CMB may contain ULVZ‐like heterogeneities. These heterogeneities exist in all lower mantle settings, including both high‐ and low‐velocity regions. Additionally, we present evidence that the Samoan ULVZ may be twice as large as previously estimated, and also present evidence for the existence of additional mega‐sized ULVZs, such as a newly discovered ULVZ located to the east of the Philippines. We provide new evidence for the ULVZ east of the Philippines through an analysis of ScP records.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020. American Geophysical Union. All Rights Reserved. This is the peer reviewed version of the following article: Thorne, M, Leng, K, Pachhai, S et al. (3 more authors) (2021) The most parsimonious ultralow‐velocity zone distribution from highly anomalous SPdKS waveforms. Geochemistry, Geophysics, Geosystems, 22 (1). e2020GC009467. ISSN 1525-2027, which has been published in final form at https://doi.org/10.1029/2020GC009467. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | core‐mantle boundary; deep subduction; hot spot volcanoes; large low‐velocity provinces; ultralow‐velocity zones; whole mantle plumes |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/R012199/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Jan 2021 15:09 |
Last Modified: | 14 Jun 2021 00:38 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1029/2020gc009467 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:170044 |