Title :

On the Influence of Pressure, Phase Transitions, and Water on Large‐Scale Seismic Anisotropy Underneath a Subduction Zone

Author(s) :

Magali, John-Keith [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Thomas, Christine [Auteur]
Westfälische Wilhelms-Universität Münster = University of Münster [WWU]
Ledoux, Estelle Elisa [Auteur]
University of Utah
Capdeville, Yann [Auteur]
Nantes Université [Nantes Univ]
Merkel, Sébastien [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Journal title :

Geochemistry, Geophysics, Geosystems

Abbreviated title :

Geochem Geophys Geosyst

Volume number :

26

Pages :

e2024GC011827

Publisher :

American Geophysical Union (AGU)

Publication date :

2025-03

HAL domain(s) :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

Seismic anisotropy mainly originates from the crystallographic preferred orientation (CPO) of minerals deformed in the convective mantle flow. While fabric transitions have been previously observed in experiments, their ...
Show more >Seismic anisotropy mainly originates from the crystallographic preferred orientation (CPO) of minerals deformed in the convective mantle flow. While fabric transitions have been previously observed in experiments, their influence on large‐scale anisotropy is not well‐documented. Here, we implement 2D geodynamic models of intra‐oceanic subduction coupled with mantle fabric modeling to investigate the combined effect of pressure ‐and water‐dependent microscopic flow properties of upper mantle and upper transition zone (UTZ) minerals, respectively, on large‐scale anisotropy. We then compare our anisotropy models with anisotropic tomography observations across the Honshu subduction zone. Our results for the upper mantle correlate well with observations, implying that the ‐dependence of olivine fabrics is sufficient to explain the variability of anisotropy. Meanwhile, a dry UTZ tends to be near‐isotropic whereas a relatively wet UTZ could produce up to azimuthal and radial anisotropy. Because water facilitates CPO development, it is therefore likely a requirement to explain the presence of anisotropy in the transition zone close to subducting slabs.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

ANR Project :

Transformations de phase, microstructures, et leur signatures sismiques dans le manteau terrestre

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2025-03-12T16:29:19Z
2025-03-12T16:37:02Z
2025-03-14T09:31:55Z