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.

Seismic imaging of the crust and upper mantle beneath Haiti and the Caribbean Sea

Seismic imaging of the crust and upper mantle beneath Haiti and the Caribbean Sea
Seismic imaging of the crust and upper mantle beneath Haiti and the Caribbean Sea
Haiti straddles the North American-Caribbean plate boundary, which accommodates oblique convergence between the two plates at a rate of 19 mm/yr. As a result, strain is partitioned acrosstwo major fault zones that transect Haiti in the north and south. The devastating 2010 MW 7.0 earthquake served to highlight our limited understanding of regional fault segmentation and itslink to plate boundary deformation. The Trans-Haiti project represented the first regional deployment of seismic stations across Haiti, recording continuous seismic data for 16 months from 2013 to 2014. 1,055 local earthquake were detected and located using a new 1-D velocity model. 437 of these earthquakes were then re-located in a tomographic inversion, retrieving the first 2-D seismic velocity model of Haiti’s crust. Hypocentre locations and low-velocity zones imaged a clear change in the structure of the Enriquillo-Plantain Garden fault zone (EPGF) in southern Haiti, transitioning from a vertical strike-slip fault in the west, to a series of south dipping oblique-slip faults across central Haiti. This was consistent with seismic anisotropy, which showed the maximum compressional stress to be orientated NNE-SSW, sub-parallel to the plate convergence direction andperpendicular to the strike of the compressional faults. In addition, anisotropic fabrics observed inthe lower crust and upper mantle highlight the coupling between the convergence across the plateboundary and the style of faulting observed in Haiti. Using data from permanent stations acrossPuerto Rico, Hispaniola (Haiti and the Dominican Republic), Jamaica and Cuba, S-to-P receiverfunctions were used to constrain crustal and lithospheric thicknesses regionally across the plateboundary. While crustal thickness was consistent at 28-34 km across the islands, these receiverfunctions highlighted a thickened lithosphere of 135 km beneath the Caribbean Large IgneousProvince (CLIP). The northern boundary of the CLIP lies in southern Haiti, beneath the expression of southward-dipping compressional faults. I suggest that this change in lithospheric thicknessmay be another factor which contributes to the observed faulting, and the transition from E-W strike-slip to NW-SE oblique-slip faults observed across southern Haiti.
University of Southampton
Possee, Daniel, James
30c7e9de-c298-469e-a9ae-c1c1caf910dc
Possee, Daniel, James
30c7e9de-c298-469e-a9ae-c1c1caf910dc
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65

Possee, Daniel, James (2020) Seismic imaging of the crust and upper mantle beneath Haiti and the Caribbean Sea. University of Southampton, Doctoral Thesis, 188pp.

Record type: Thesis (Doctoral)

Abstract

Haiti straddles the North American-Caribbean plate boundary, which accommodates oblique convergence between the two plates at a rate of 19 mm/yr. As a result, strain is partitioned acrosstwo major fault zones that transect Haiti in the north and south. The devastating 2010 MW 7.0 earthquake served to highlight our limited understanding of regional fault segmentation and itslink to plate boundary deformation. The Trans-Haiti project represented the first regional deployment of seismic stations across Haiti, recording continuous seismic data for 16 months from 2013 to 2014. 1,055 local earthquake were detected and located using a new 1-D velocity model. 437 of these earthquakes were then re-located in a tomographic inversion, retrieving the first 2-D seismic velocity model of Haiti’s crust. Hypocentre locations and low-velocity zones imaged a clear change in the structure of the Enriquillo-Plantain Garden fault zone (EPGF) in southern Haiti, transitioning from a vertical strike-slip fault in the west, to a series of south dipping oblique-slip faults across central Haiti. This was consistent with seismic anisotropy, which showed the maximum compressional stress to be orientated NNE-SSW, sub-parallel to the plate convergence direction andperpendicular to the strike of the compressional faults. In addition, anisotropic fabrics observed inthe lower crust and upper mantle highlight the coupling between the convergence across the plateboundary and the style of faulting observed in Haiti. Using data from permanent stations acrossPuerto Rico, Hispaniola (Haiti and the Dominican Republic), Jamaica and Cuba, S-to-P receiverfunctions were used to constrain crustal and lithospheric thicknesses regionally across the plateboundary. While crustal thickness was consistent at 28-34 km across the islands, these receiverfunctions highlighted a thickened lithosphere of 135 km beneath the Caribbean Large IgneousProvince (CLIP). The northern boundary of the CLIP lies in southern Haiti, beneath the expression of southward-dipping compressional faults. I suggest that this change in lithospheric thicknessmay be another factor which contributes to the observed faulting, and the transition from E-W strike-slip to NW-SE oblique-slip faults observed across southern Haiti.

Text
Possee, Daniel_PhD_Thesis_April_20 - Author's Original
Available under License University of Southampton Thesis Licence.
Download (69MB)

More information

Published date: 20 April 2020

Identifiers

Local EPrints ID: 440690
URI: http://eprints.soton.ac.uk/id/eprint/440690
PURE UUID: 3d1def02-44ef-4b2b-ab18-0d2d8f9f2a3c
ORCID for Derek Keir: ORCID iD orcid.org/0000-0001-8787-8446

Catalogue record

Date deposited: 13 May 2020 16:36
Last modified: 20 Jan 2021 05:01

Export record

Contributors

Author: Daniel, James Possee
Thesis advisor: Derek Keir ORCID iD

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.

×