The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Spatial variations in crustal and mantle anisotropy across the North American‐Caribbean boundary on Haiti

Spatial variations in crustal and mantle anisotropy across the North American‐Caribbean boundary on Haiti
Spatial variations in crustal and mantle anisotropy across the North American‐Caribbean boundary on Haiti
Haiti, on the island of Hispaniola, is situated across the North American‐Caribbean plate boundary at the transition point between oblique subduction in the east and a transform plate boundary in the west. Here we use shear wave splitting measurements from S waves of local (0‐50 km) and intermediate depth (50‐150 km) earthquakes as well as SK(K)S phases from teleseismic earthquakes to ascertain good spatial and vertical resolution of the azimuthal anisotropic structure. This allows us to place new constraints on the pattern of deformation in the crust and mantle beneath this transitional region. SK(K)S results are dominated by plate boundary parallel (E‐W) fast directions with ~1.9 s delay times, indicating sub‐slab trench parallel mantle flow is continuing westward along the plate boundary. Intermediate depth earthquakes originating within the subducting North American plate show a mean fast polarization direction of 065° and delay time of 0.46 s, sub‐parallel to the relative plate motion between the Caribbean and North American plates (070°). We suggest a basal shear zone within the lower ductile crust and upper lithospheric mantle as being a potential major source of anisotropy above the subducting slab. Upper crustal anisotropy is isolated using shear wave splitting measurements on local seismicity, which show consistent delay times on the order of 0.2 s. The fast polarization directions indicate the crustal anisotropy is controlled by the fault networks in close proximity to the major strike‐slip faults, which bisect the north and south of Haiti, and by the regional stress field where faulting is less pervasive.
Caribbean, Haiti, anisotropy, plate boundary, shear wave splitting
0148-0227
Possee, Daniel, James
30c7e9de-c298-469e-a9ae-c1c1caf910dc
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Harmon, Nicholas
10d11a16-b8b0-4132-9354-652e72d8e830
Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Eakin, Caroline M
767ea10a-757b-4db5-8705-0c79368f8606
Rolandone, Frédérique
5adfaa49-10e8-40d8-bace-bee9dd39f95a
Leroy, Sylvie
627c503b-1036-41fc-a24c-3d09954fab0a
Corbeau, Jordane
a71d8ba4-f19d-43ac-9c4e-ddcef42ff745
Stuart, Graham
e3faae46-fef1-45f4-94cd-50bd675fae92
Boisson, Dominique
7c461abc-daf8-4ded-8832-c47412b9f59a
Momplaisir, Roberte
8707114c-90ad-46d3-af3a-10decf89c7ac
Prépetit, Claude
6ab89f7a-2d0c-4247-a5e4-0ab688864c8c
Possee, Daniel, James
30c7e9de-c298-469e-a9ae-c1c1caf910dc
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Harmon, Nicholas
10d11a16-b8b0-4132-9354-652e72d8e830
Rychert, Catherine
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Eakin, Caroline M
767ea10a-757b-4db5-8705-0c79368f8606
Rolandone, Frédérique
5adfaa49-10e8-40d8-bace-bee9dd39f95a
Leroy, Sylvie
627c503b-1036-41fc-a24c-3d09954fab0a
Corbeau, Jordane
a71d8ba4-f19d-43ac-9c4e-ddcef42ff745
Stuart, Graham
e3faae46-fef1-45f4-94cd-50bd675fae92
Boisson, Dominique
7c461abc-daf8-4ded-8832-c47412b9f59a
Momplaisir, Roberte
8707114c-90ad-46d3-af3a-10decf89c7ac
Prépetit, Claude
6ab89f7a-2d0c-4247-a5e4-0ab688864c8c

Possee, Daniel, James, Keir, Derek, Harmon, Nicholas, Rychert, Catherine, Eakin, Caroline M, Rolandone, Frédérique, Leroy, Sylvie, Corbeau, Jordane, Stuart, Graham, Boisson, Dominique, Momplaisir, Roberte and Prépetit, Claude (2020) Spatial variations in crustal and mantle anisotropy across the North American‐Caribbean boundary on Haiti. Journal of Geophysical Research, 125 (6), [e2019JB018438]. (doi:10.1029/2019JB018438).

Record type: Article

Abstract

Haiti, on the island of Hispaniola, is situated across the North American‐Caribbean plate boundary at the transition point between oblique subduction in the east and a transform plate boundary in the west. Here we use shear wave splitting measurements from S waves of local (0‐50 km) and intermediate depth (50‐150 km) earthquakes as well as SK(K)S phases from teleseismic earthquakes to ascertain good spatial and vertical resolution of the azimuthal anisotropic structure. This allows us to place new constraints on the pattern of deformation in the crust and mantle beneath this transitional region. SK(K)S results are dominated by plate boundary parallel (E‐W) fast directions with ~1.9 s delay times, indicating sub‐slab trench parallel mantle flow is continuing westward along the plate boundary. Intermediate depth earthquakes originating within the subducting North American plate show a mean fast polarization direction of 065° and delay time of 0.46 s, sub‐parallel to the relative plate motion between the Caribbean and North American plates (070°). We suggest a basal shear zone within the lower ductile crust and upper lithospheric mantle as being a potential major source of anisotropy above the subducting slab. Upper crustal anisotropy is isolated using shear wave splitting measurements on local seismicity, which show consistent delay times on the order of 0.2 s. The fast polarization directions indicate the crustal anisotropy is controlled by the fault networks in close proximity to the major strike‐slip faults, which bisect the north and south of Haiti, and by the regional stress field where faulting is less pervasive.

Text
2019JB018438 - Accepted Manuscript
Restricted to Repository staff only
Request a copy

More information

Accepted/In Press date: 5 May 2020
e-pub ahead of print date: 9 May 2020
Published date: June 2020
Keywords: Caribbean, Haiti, anisotropy, plate boundary, shear wave splitting

Identifiers

Local EPrints ID: 441085
URI: http://eprints.soton.ac.uk/id/eprint/441085
ISSN: 0148-0227
PURE UUID: 4420ded8-578e-4f39-8825-185cff64e7d0
ORCID for Derek Keir: ORCID iD orcid.org/0000-0001-8787-8446
ORCID for Nicholas Harmon: ORCID iD orcid.org/0000-0002-0731-768X

Catalogue record

Date deposited: 29 May 2020 16:31
Last modified: 26 Nov 2021 02:57

Export record

Altmetrics

Contributors

Author: Daniel, James Possee
Author: Derek Keir ORCID iD
Author: Nicholas Harmon ORCID iD
Author: Caroline M Eakin
Author: Frédérique Rolandone
Author: Sylvie Leroy
Author: Jordane Corbeau
Author: Graham Stuart
Author: Dominique Boisson
Author: Roberte Momplaisir
Author: Claude Prépetit

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×