The development of seismic anisotropy below South-Central Alaska: Evidence from local earthquake shear-wave splitting

Karlowska, Eliza ORCID: https://orcid.org/0000-0003-2401-0871, Bastow, Ian, Rondenay, Stéphane, Martin-Short, Robert and Allen, Richard (2021) The development of seismic anisotropy below South-Central Alaska: Evidence from local earthquake shear-wave splitting. Geophysical Journal International, 225 (1). 548–554. ISSN 0956-540X

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Abstract

The Transportable Array in south-central Alaska spans several subduction zone features: backarc, forearc and volcanic arc, making it an ideal tool to study subduction zone anisotropy. Shear wave splitting analysis of 157 local earthquakes of m b ≥ 3.0 that occurred between 2014 and 2019 yields 210 high-quality measurements at 23 stations. Splitting delay times (δt) are generally small (δt ≈ 0.3 s), increasing with distance from the trench. Arc-parallel fast directions, φ, are only seen in the forearc, but rotate to arc-perpendicular φ in the backarc. Observed φ values generally do not parallel teleseismic SKS splitting results, implying that the latter is sensitive primarily to subslab mantle flow, not mantle wedge dynamics. The forearc local-earthquake signal likely originates from anisotropic serpentinite in fractures atop the subducting Pacific Plate, with possible additional signal coming from fractures in the North American crust. Mantle wedge corner flow, potentially with additional arc-perpendicular anisotropy in the subducting slab, explains backarc anisotropy.

Item Type:	Article
Uncontrolled Keywords:	north america,seismic anisotropy,subduction zone processes,volcanic arc processes,geophysics,geochemistry and petrology ,/dk/atira/pure/subjectarea/asjc/1900/1908
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	02 Feb 2021 01:02
Last Modified:	22 Oct 2022 08:33
URI:	https://ueaeprints.uea.ac.uk/id/eprint/79129
DOI:	10.1093/gji/ggaa603

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