Upper Mantle Anisotropy and Flow Beneath the Pacific Ocean Revealed by Differential PS‐SKS Splitting

Autor: Jonathan Wolf, Maureen D. Long
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Geophysical Research Letters, Vol 50, Iss 16, Pp n/a-n/a (2023)
Druh dokumentu: article
ISSN: 1944-8007
0094-8276
DOI: 10.1029/2023GL104402
Popis: Abstract Upper mantle anisotropy has been mapped beneath continents at high spatial resolution. Beneath the oceans, however, shear wave splitting constraints on upper mantle anisotropy are sparse, due to the paucity of seismic receivers. A technique that does not require the availability of seismic stations close to the region under study is differential PS‐SKS splitting. Here, we use global wavefield simulations to investigate circumstances under which PS‐SKS splitting can be applied, and then use this technique to measure upper mantle anisotropy beneath the Pacific Ocean basin. Our results demonstrate that upper mantle anisotropy in our study region mostly reflects shearing due to the Pacific plate. North of Fiji, we observe a rotation of fast polarization directions, away from the direction of absolute plate motion of the Pacific plate. This may reflect far‐field mantle flow effects associated with the subduction of the Australian plate beneath the Pacific.
Databáze: Directory of Open Access Journals
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